fs: fix out-of-bounds write in mkdtemp for long prefixes - #64770

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nodejs-github-bot merged 1 commit into
nodejs:mainfrom
frandle331-yh:fix-mkdtemp-oob-write
Aug 20, 2026
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fs: fix out-of-bounds write in mkdtemp for long prefixes#64770
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frandle331-yh:fix-mkdtemp-oob-write

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@frandle331-yhfrandle331-yh commented Jul 27, 2026

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Mkdtemp() allocated the template buffer as length + strlen("XXXXXX"),
leaving no room for the terminating NUL byte that snprintf() writes. For
a single-byte prefix long enough to force the heap allocation path
(length + 6 > the stack-buffer threshold), snprintf() wrote the six 'X'
characters plus its NUL one byte past the end of the buffer -- a 1-byte
heap-buffer-overflow flagged by AddressSanitizer.

Allocate one extra byte for the NUL terminator, matching the + 1
already used by the sibling allocations in the same file.

Signed-off-by: frandle331-yh s1240100@gmail.com

@nodejs-github-botnodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. fs Issues and PRs related to file-system APIs and the fs module. needs-ci PRs that need a full CI run. labels Jul 27, 2026
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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.13%. Comparing base (54a5095) to head (a702884).
⚠️ Report is 402 commits behind head on main.

Additional details and impacted files
@@ Coverage Diff @@## main #64770 +/- ##
==========================================
- Coverage 90.14% 90.13% -0.01% 
==========================================
Files 744 744 Lines 242518 242519 +1 Branches 45685 45685 ==========================================
- Hits 218611 218599 -12 - Misses 15396 15406 +10 - Partials 8511 8514 +3
Files with missing linesCoverage Δ
src/node_file.cc74.20% <100.00%> (+<0.01%)⬆️

... and 32 files with indirect coverage changes

🚀 New features to boost your workflow:
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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Comment threadsrc/node_file.cc Outdated
@frandle331-yh
fs: fix out-of-bounds write in mkdtemp for long prefixes
a702884
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
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@Renegade334Renegade334 added author ready PRs with CI started, the required approvals, and no outstanding review comments. request-ci Add this label to start a Jenkins CI on a PR. labels Jul 27, 2026
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frandle331-yh commented Jul 28, 2026

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It looks like the macOS CI failed due to a timeout in parallel/test-debugger-break, which seems unrelated to my fs.mkdtemp changes (likely a flaky test).
Could you please re-run the CI for me?

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CI: https://ci.nodejs.org/job/node-test-pull-request/75261/

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It looks like the CI failed again (node-test-commit, etc.), but I don't have permission to view the Jenkins logs.
Could anyone please share the error logs with me, or let me know if these failures are related to my changes?

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CI: https://ci.nodejs.org/job/node-test-pull-request/75683/

@trivikrtrivikr added the commit-queue PRs queued for automated landing through the Commit Queue. label Aug 20, 2026
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nodejs-github-bot merged commit 9472421 into nodejs:mainAug 20, 2026
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aduh95 pushed a commit that referenced this pull request Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
54225e1
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
aduh95 pushed a commit that referenced this pull request Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
992af05
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
@github-actionsgithub-actionsBot mentioned this pull request Aug 25, 2026
Merged
aduh95 pushed a commit that referenced this pull request Aug 27, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
d67925f
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
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@frandle331-yh@nodejs-github-bot@Renegade334@trivikr
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
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})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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fs: fix out-of-bounds write in mkdtemp for long prefixes - #64770
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frandle331-yh:fix-mkdtemp-oob-write
Aug 20, 2026
Merged
fs: fix out-of-bounds write in mkdtemp for long prefixes#64770
nodejs-github-bot merged 1 commit into
nodejs:mainfrom 
frandle331-yh:fix-mkdtemp-oob-write
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@frandle331-yhfrandle331-yh
commented
Jul 27, 2026

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Mkdtemp() allocated the template buffer as length + strlen("XXXXXX"),

leaving no room for the terminating NUL byte that snprintf() writes. For

a single-byte prefix long enough to force the heap allocation path

(length + 6 > the stack-buffer threshold), snprintf() wrote the six 'X'

characters plus its NUL one byte past the end of the buffer -- a 1-byte

heap-buffer-overflow flagged by AddressSanitizer.
Allocate one extra byte for the NUL terminator, matching the + 1

already used by the sibling allocations in the same file.
Signed-off-by: frandle331-yh s1240100@gmail.com
@nodejs-github-botnodejs-github-bot
added

c++
Issues and PRs that require attention from people who are familiar with C++.
fs
Issues and PRs related to file-system APIs and the fs module.
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.13%. Comparing base (54a5095) to head (a702884).
⚠️ Report is 402 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #64770 +/- ##
==========================================
- Coverage 90.14% 90.13% -0.01% 
==========================================
Files 744 744 Lines 242518 242519 +1 Branches 45685 45685 ==========================================
- Hits 218611 218599 -12 - Misses 15396 15406 +10 - Partials 8511 8514 +3 
Files with missing linesCoverage Δ
src/node_file.cc74.20% <100.00%> (+<0.01%)⬆️
... and 32 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
Renegade334
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View reviewed changes
Comment threadsrc/node_file.cc
Outdated

@frandle331-yh
fs: fix out-of-bounds write in mkdtemp for long prefixes
a702884
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
Renegade334
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Jul 28, 2026

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It looks like the macOS CI failed due to a timeout in parallel/test-debugger-break, which seems unrelated to my fs.mkdtemp changes (likely a flaky test).

Could you please re-run the CI for me?
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CI: https://ci.nodejs.org/job/node-test-pull-request/75261/
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It looks like the CI failed again (node-test-commit, etc.), but I don't have permission to view the Jenkins logs.

Could anyone please share the error logs with me, or let me know if these failures are related to my changes?
@nodejs-github-bot
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CI: https://ci.nodejs.org/job/node-test-pull-request/75683/
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aduh95 pushed a commit
that referenced
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Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
54225e1
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
992af05
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
@github-actionsgithub-actionsBot
mentioned this pull request
Aug 25, 2026
 Merged

aduh95 pushed a commit
that referenced
this pull request
Aug 27, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
d67925f
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
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, 'i');
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})();
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try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fs: fix out-of-bounds write in mkdtemp for long prefixes - #64770
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frandle331-yh:fix-mkdtemp-oob-write
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Merged
fs: fix out-of-bounds write in mkdtemp for long prefixes#64770
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Mkdtemp() allocated the template buffer as length + strlen("XXXXXX"),

leaving no room for the terminating NUL byte that snprintf() writes. For

a single-byte prefix long enough to force the heap allocation path

(length + 6 > the stack-buffer threshold), snprintf() wrote the six 'X'

characters plus its NUL one byte past the end of the buffer -- a 1-byte

heap-buffer-overflow flagged by AddressSanitizer.
Allocate one extra byte for the NUL terminator, matching the + 1

already used by the sibling allocations in the same file.
Signed-off-by: frandle331-yh s1240100@gmail.com
@nodejs-github-botnodejs-github-bot
added

c++
Issues and PRs that require attention from people who are familiar with C++.
fs
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.13%. Comparing base (54a5095) to head (a702884).
⚠️ Report is 402 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #64770 +/- ##
==========================================
- Coverage 90.14% 90.13% -0.01% 
==========================================
Files 744 744 Lines 242518 242519 +1 Branches 45685 45685 ==========================================
- Hits 218611 218599 -12 - Misses 15396 15406 +10 - Partials 8511 8514 +3 
Files with missing linesCoverage Δ
src/node_file.cc74.20% <100.00%> (+<0.01%)⬆️
... and 32 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
Renegade334
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View reviewed changes
Comment threadsrc/node_file.cc
Outdated

@frandle331-yh
fs: fix out-of-bounds write in mkdtemp for long prefixes
a702884
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
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It looks like the macOS CI failed due to a timeout in parallel/test-debugger-break, which seems unrelated to my fs.mkdtemp changes (likely a flaky test).

Could you please re-run the CI for me?
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It looks like the CI failed again (node-test-commit, etc.), but I don't have permission to view the Jenkins logs.

Could anyone please share the error logs with me, or let me know if these failures are related to my changes?
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@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
54225e1
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
992af05
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
@github-actionsgithub-actionsBot
mentioned this pull request
Aug 25, 2026
 Merged

aduh95 pushed a commit
that referenced
this pull request
Aug 27, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
d67925f
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fs: fix out-of-bounds write in mkdtemp for long prefixes - #64770
Merged
nodejs-github-bot merged 1 commit into
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frandle331-yh:fix-mkdtemp-oob-write
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Merged
fs: fix out-of-bounds write in mkdtemp for long prefixes#64770
nodejs-github-bot merged 1 commit into
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frandle331-yh:fix-mkdtemp-oob-write
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Jul 27, 2026

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Mkdtemp() allocated the template buffer as length + strlen("XXXXXX"),

leaving no room for the terminating NUL byte that snprintf() writes. For

a single-byte prefix long enough to force the heap allocation path

(length + 6 > the stack-buffer threshold), snprintf() wrote the six 'X'

characters plus its NUL one byte past the end of the buffer -- a 1-byte

heap-buffer-overflow flagged by AddressSanitizer.
Allocate one extra byte for the NUL terminator, matching the + 1

already used by the sibling allocations in the same file.
Signed-off-by: frandle331-yh s1240100@gmail.com
@nodejs-github-botnodejs-github-bot
added

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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.13%. Comparing base (54a5095) to head (a702884).
⚠️ Report is 402 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #64770 +/- ##
==========================================
- Coverage 90.14% 90.13% -0.01% 
==========================================
Files 744 744 Lines 242518 242519 +1 Branches 45685 45685 ==========================================
- Hits 218611 218599 -12 - Misses 15396 15406 +10 - Partials 8511 8514 +3 
Files with missing linesCoverage Δ
src/node_file.cc74.20% <100.00%> (+<0.01%)⬆️
... and 32 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
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Comment threadsrc/node_file.cc
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@frandle331-yh
fs: fix out-of-bounds write in mkdtemp for long prefixes
a702884
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
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Jul 28, 2026

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It looks like the macOS CI failed due to a timeout in parallel/test-debugger-break, which seems unrelated to my fs.mkdtemp changes (likely a flaky test).

Could you please re-run the CI for me?
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CI: https://ci.nodejs.org/job/node-test-pull-request/75261/
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It looks like the CI failed again (node-test-commit, etc.), but I don't have permission to view the Jenkins logs.

Could anyone please share the error logs with me, or let me know if these failures are related to my changes?
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CI: https://ci.nodejs.org/job/node-test-pull-request/75683/
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aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
54225e1
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
992af05
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
@github-actionsgithub-actionsBot
mentioned this pull request
Aug 25, 2026
 Merged

aduh95 pushed a commit
that referenced
this pull request
Aug 27, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
d67925f
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
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@frandle331-yh@nodejs-github-bot@Renegade334@trivikr

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
fs: fix out-of-bounds write in mkdtemp for long prefixes - #64770
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nodejs-github-bot merged 1 commit into
nodejs:mainfrom 
frandle331-yh:fix-mkdtemp-oob-write
Aug 20, 2026
Merged
fs: fix out-of-bounds write in mkdtemp for long prefixes#64770
nodejs-github-bot merged 1 commit into
nodejs:mainfrom 
frandle331-yh:fix-mkdtemp-oob-write
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Jul 27, 2026

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Mkdtemp() allocated the template buffer as length + strlen("XXXXXX"),

leaving no room for the terminating NUL byte that snprintf() writes. For

a single-byte prefix long enough to force the heap allocation path

(length + 6 > the stack-buffer threshold), snprintf() wrote the six 'X'

characters plus its NUL one byte past the end of the buffer -- a 1-byte

heap-buffer-overflow flagged by AddressSanitizer.
Allocate one extra byte for the NUL terminator, matching the + 1

already used by the sibling allocations in the same file.
Signed-off-by: frandle331-yh s1240100@gmail.com
@nodejs-github-botnodejs-github-bot
added

c++
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.13%. Comparing base (54a5095) to head (a702884).
⚠️ Report is 402 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #64770 +/- ##
==========================================
- Coverage 90.14% 90.13% -0.01% 
==========================================
Files 744 744 Lines 242518 242519 +1 Branches 45685 45685 ==========================================
- Hits 218611 218599 -12 - Misses 15396 15406 +10 - Partials 8511 8514 +3 
Files with missing linesCoverage Δ
src/node_file.cc74.20% <100.00%> (+<0.01%)⬆️
... and 32 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
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Comment threadsrc/node_file.cc
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@frandle331-yh
fs: fix out-of-bounds write in mkdtemp for long prefixes
a702884
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
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@frandle331-yh
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Jul 28, 2026

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It looks like the macOS CI failed due to a timeout in parallel/test-debugger-break, which seems unrelated to my fs.mkdtemp changes (likely a flaky test).

Could you please re-run the CI for me?
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It looks like the CI failed again (node-test-commit, etc.), but I don't have permission to view the Jenkins logs.

Could anyone please share the error logs with me, or let me know if these failures are related to my changes?
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CI: https://ci.nodejs.org/job/node-test-pull-request/75683/
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@nodejs-github-bot
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merged commit 9472421
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74 of 77 checks passed

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Landed in 9472421
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Aug 20, 2026
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
54225e1
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
992af05
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
@github-actionsgithub-actionsBot
mentioned this pull request
Aug 25, 2026
 Merged

aduh95 pushed a commit
that referenced
this pull request
Aug 27, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
d67925f
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fs: fix out-of-bounds write in mkdtemp for long prefixes - #64770
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nodejs-github-bot merged 1 commit into
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frandle331-yh:fix-mkdtemp-oob-write
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Merged
fs: fix out-of-bounds write in mkdtemp for long prefixes#64770
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frandle331-yh:fix-mkdtemp-oob-write
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Mkdtemp() allocated the template buffer as length + strlen("XXXXXX"),

leaving no room for the terminating NUL byte that snprintf() writes. For

a single-byte prefix long enough to force the heap allocation path

(length + 6 > the stack-buffer threshold), snprintf() wrote the six 'X'

characters plus its NUL one byte past the end of the buffer -- a 1-byte

heap-buffer-overflow flagged by AddressSanitizer.
Allocate one extra byte for the NUL terminator, matching the + 1

already used by the sibling allocations in the same file.
Signed-off-by: frandle331-yh s1240100@gmail.com
@nodejs-github-botnodejs-github-bot
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.13%. Comparing base (54a5095) to head (a702884).
⚠️ Report is 402 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #64770 +/- ##
==========================================
- Coverage 90.14% 90.13% -0.01% 
==========================================
Files 744 744 Lines 242518 242519 +1 Branches 45685 45685 ==========================================
- Hits 218611 218599 -12 - Misses 15396 15406 +10 - Partials 8511 8514 +3 
Files with missing linesCoverage Δ
src/node_file.cc74.20% <100.00%> (+<0.01%)⬆️
... and 32 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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@frandle331-yh
fs: fix out-of-bounds write in mkdtemp for long prefixes
a702884
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
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Jul 28, 2026

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It looks like the macOS CI failed due to a timeout in parallel/test-debugger-break, which seems unrelated to my fs.mkdtemp changes (likely a flaky test).

Could you please re-run the CI for me?
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CI: https://ci.nodejs.org/job/node-test-pull-request/75261/
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It looks like the CI failed again (node-test-commit, etc.), but I don't have permission to view the Jenkins logs.

Could anyone please share the error logs with me, or let me know if these failures are related to my changes?
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aduh95 pushed a commit
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Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
54225e1
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
992af05
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
@github-actionsgithub-actionsBot
mentioned this pull request
Aug 25, 2026
 Merged

aduh95 pushed a commit
that referenced
this pull request
Aug 27, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
d67925f
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
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@frandle331-yh@nodejs-github-bot@Renegade334@trivikr

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fs: fix out-of-bounds write in mkdtemp for long prefixes - #64770
Merged
nodejs-github-bot merged 1 commit into
nodejs:mainfrom 
frandle331-yh:fix-mkdtemp-oob-write
Aug 20, 2026
Merged
fs: fix out-of-bounds write in mkdtemp for long prefixes#64770
nodejs-github-bot merged 1 commit into
nodejs:mainfrom 
frandle331-yh:fix-mkdtemp-oob-write
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Jul 27, 2026

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Mkdtemp() allocated the template buffer as length + strlen("XXXXXX"),

leaving no room for the terminating NUL byte that snprintf() writes. For

a single-byte prefix long enough to force the heap allocation path

(length + 6 > the stack-buffer threshold), snprintf() wrote the six 'X'

characters plus its NUL one byte past the end of the buffer -- a 1-byte

heap-buffer-overflow flagged by AddressSanitizer.
Allocate one extra byte for the NUL terminator, matching the + 1

already used by the sibling allocations in the same file.
Signed-off-by: frandle331-yh s1240100@gmail.com
@nodejs-github-botnodejs-github-bot
added

c++
Issues and PRs that require attention from people who are familiar with C++.
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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.13%. Comparing base (54a5095) to head (a702884).
⚠️ Report is 402 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #64770 +/- ##
==========================================
- Coverage 90.14% 90.13% -0.01% 
==========================================
Files 744 744 Lines 242518 242519 +1 Branches 45685 45685 ==========================================
- Hits 218611 218599 -12 - Misses 15396 15406 +10 - Partials 8511 8514 +3 
Files with missing linesCoverage Δ
src/node_file.cc74.20% <100.00%> (+<0.01%)⬆️
... and 32 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
Renegade334
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View reviewed changes
Comment threadsrc/node_file.cc
Outdated

@frandle331-yh
fs: fix out-of-bounds write in mkdtemp for long prefixes
a702884
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
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Jul 28, 2026

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It looks like the macOS CI failed due to a timeout in parallel/test-debugger-break, which seems unrelated to my fs.mkdtemp changes (likely a flaky test).

Could you please re-run the CI for me?
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It looks like the CI failed again (node-test-commit, etc.), but I don't have permission to view the Jenkins logs.

Could anyone please share the error logs with me, or let me know if these failures are related to my changes?
@nodejs-github-bot
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CI: https://ci.nodejs.org/job/node-test-pull-request/75683/
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@nodejs-github-bot
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merged commit 9472421
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Aug 20, 2026
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
54225e1
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
992af05
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
@github-actionsgithub-actionsBot
mentioned this pull request
Aug 25, 2026
 Merged

aduh95 pushed a commit
that referenced
this pull request
Aug 27, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
d67925f
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
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@frandle331-yh@nodejs-github-bot@Renegade334@trivikr

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
fs: fix out-of-bounds write in mkdtemp for long prefixes - #64770
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nodejs-github-bot merged 1 commit into
nodejs:mainfrom 
frandle331-yh:fix-mkdtemp-oob-write
Aug 20, 2026
Merged
fs: fix out-of-bounds write in mkdtemp for long prefixes#64770
nodejs-github-bot merged 1 commit into
nodejs:mainfrom 
frandle331-yh:fix-mkdtemp-oob-write
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Mkdtemp() allocated the template buffer as length + strlen("XXXXXX"),

leaving no room for the terminating NUL byte that snprintf() writes. For

a single-byte prefix long enough to force the heap allocation path

(length + 6 > the stack-buffer threshold), snprintf() wrote the six 'X'

characters plus its NUL one byte past the end of the buffer -- a 1-byte

heap-buffer-overflow flagged by AddressSanitizer.
Allocate one extra byte for the NUL terminator, matching the + 1

already used by the sibling allocations in the same file.
Signed-off-by: frandle331-yh s1240100@gmail.com
@nodejs-github-botnodejs-github-bot
added

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Codecov Report
✅ All modified and coverable lines are covered by tests.

✅ Project coverage is 90.13%. Comparing base (54a5095) to head (a702884).
⚠️ Report is 402 commits behind head on main.
Additional details and impacted files
@@ Coverage Diff @@## main #64770 +/- ##
==========================================
- Coverage 90.14% 90.13% -0.01% 
==========================================
Files 744 744 Lines 242518 242519 +1 Branches 45685 45685 ==========================================
- Hits 218611 218599 -12 - Misses 15396 15406 +10 - Partials 8511 8514 +3 
Files with missing linesCoverage Δ
src/node_file.cc74.20% <100.00%> (+<0.01%)⬆️
... and 32 files with indirect coverage changes
 🚀 New features to boost your workflow: 
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
Renegade334
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View reviewed changes
Comment threadsrc/node_file.cc
Outdated

@frandle331-yh
fs: fix out-of-bounds write in mkdtemp for long prefixes
a702884
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
Renegade334
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Thanks!
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@frandle331-yh
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Jul 28, 2026

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It looks like the macOS CI failed due to a timeout in parallel/test-debugger-break, which seems unrelated to my fs.mkdtemp changes (likely a flaky test).

Could you please re-run the CI for me?
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CI: https://ci.nodejs.org/job/node-test-pull-request/75261/
@frandle331-yh
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It looks like the CI failed again (node-test-commit, etc.), but I don't have permission to view the Jenkins logs.

Could anyone please share the error logs with me, or let me know if these failures are related to my changes?
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CI: https://ci.nodejs.org/job/node-test-pull-request/75683/
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aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
54225e1
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
aduh95 pushed a commit
that referenced
this pull request
Aug 25, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
992af05
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
@github-actionsgithub-actionsBot
mentioned this pull request
Aug 25, 2026
 Merged

aduh95 pushed a commit
that referenced
this pull request
Aug 27, 2026
@frandle331-yh@aduh95
fs: fix out-of-bounds write in mkdtemp for long prefixes
d67925f
Mkdtemp() allocated the template buffer as `length + strlen("XXXXXX")`,
leaving no room for the terminating NUL byte. For a single-byte prefix
long enough to force the heap allocation path (length + 6 > the
stack-buffer threshold), the terminating NUL was written one byte past
the end of the buffer -- a 1-byte heap-buffer-overflow flagged by
AddressSanitizer.
Allocate room for the terminating NUL, copy the suffix, and use
SetLengthAndZeroTerminate to set the correct length and write the
terminator, following the MaybeStackBuffer paradigm used elsewhere in
this file.
Signed-off-by: frandle331-yh <s1240100@gmail.com>
PR-URL: #64770
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>
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