chore(deps): update dependency js-cookie to v3.0.7 [security]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
js-cookie	3.0.5 → 3.0.7

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JavaScript Cookie: Per-instance prototype hijack in assign() enables cookie-attribute injection

CVE-2026-46625 / GHSA-qjx8-664m-686j

More information

Details

Summary

js-cookie's internal assign() helper copies properties with for...in + plain assignment. When the source object is produced by JSON.parse, the JSON object's "__proto__" member is an own enumerable property, so the for…in enumerates it and the target[key] = source[key] write triggers the Object.prototype.__proto__ setter on the fresh target ({}). The result is a per-instance prototype hijack: Object.prototype itself is untouched, but the merged attributes object now inherits attacker-controlled keys.

Because the consuming set() function then enumerates the merged object with another for...in, every key the attacker placed on the polluted prototype lands in the resulting Set-Cookie string as an attribute pair. The attacker can set domain=, secure=, samesite=, expires=, and path= on cookies whose attributes the developer thought were locked down.

Impact

Any application that forwards a JSON-derived object as the attributes argument to Cookies.set, Cookies.remove, Cookies.withAttributes, or Cookies.withConverter is vulnerable. This is the standard pattern when cookie configuration comes from a backend:

constcfg=awaitfetch('/config').then(r=>r.json());Cookies.set('session',token,cfg.cookieAttrs);// cfg.cookieAttrs influenced by attacker

A payload of {"__proto__":{"domain":"evil.example","secure":"false","samesite":"None"}} causes js-cookie to emit:

Set-Cookie: session=TOKEN; path=/; domain=evil.example; secure=false; samesite=None

Affected code

// src/assign.mjs — full fileexportdefaultfunction(target){for(vari=1;i<arguments.length;i++){varsource=arguments[i]for(varkeyinsource){// includes own enumerable '__proto__'target[key]=source[key]// [[Set]] form - fires __proto__ setter}}returntarget}

Proof of concept

Node 22.11.0, no third-party deps:

Environment setup

mkdir -p /tmp/jscookie-poc &&cd /tmp/jscookie-poc
npm init -y
npm i js-cookie

PoC

ubuntu@kuber:/tmp/jscookie-poc$catpoc.mjsletlastSetCookie='';globalThis.document={getcookie(){return'';},setcookie(v){lastSetCookie=v;}};const{default: Cookies}=awaitimport('js-cookie');constattackerAttrs=JSON.parse('{"__proto__":{"secure":"false","domain":"evil.com","samesite":"None","expires":-1}}');Cookies.set('session','TOKEN',attackerAttrs);console.log('Set-Cookie that js-cookie wrote to document.cookie:');console.log(lastSetCookie);

Execution:

Suggested patch

--- a/src/assign.mjs+++ b/src/assign.mjs
@@
export default function (target) {
for (var i = 1; i < arguments.length; i++) {
var source = arguments[i]
- for (var key in source) {- target[key] = source[key]- }+ for (var key in source) {+ if (key === '__proto__' || key === 'constructor' || key === 'prototype') continue+ Object.defineProperty(target, key, {+ value: source[key],+ writable: true,+ enumerable: true,+ configurable: true,+ })+ }
}
return target
}

Equivalent one-liner alternative - iterate own names only and filter:

for(constkeyofObject.getOwnPropertyNames(source)){if(key==='__proto__')continuetarget[key]=source[key]}

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

References

• https://github.com/js-cookie/js-cookie/security/advisories/GHSA-qjx8-664m-686j
• https://nvd.nist.gov/vuln/detail/CVE-2026-46625
• https://github.com/js-cookie/js-cookie/commit/eb3c40e89731e99b8970faaf35ddad249c6c0020
• https://github.com/js-cookie/js-cookie/releases/tag/v3.0.7
• https://github.com/advisories/GHSA-qjx8-664m-686j

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Release Notes

js-cookie/js-cookie (js-cookie)

v3.0.7

Compare Source

• Prevent cookie attribute injection: CVE-2026-46625 (eb3c40e)
• Add Partitioned attribute to readme (b994768)
• Publish to npm registry via trusted publisher exclusively (4dc71be)
• Ensure consistent behaviour for get('name') + get() (1953d30)

v3.0.6

Compare Source

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[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
dist/index.js	541 B (0%)	11 ms (0%)	40 ms (+470.53% 🔺)	51 ms

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.00%. Comparing base (7c7be48) to head (1fefe68).

Additional details and impacted files

@@ Coverage Diff @@## master #1346 +/- ##
=======================================
Coverage 90.00% 90.00% =======================================
Files 3 3 Lines 80 80 Branches 20 20 =======================================
Hits 72 72 Misses 6 6 Partials 2 2 

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