fix(csp): allow https images in markdown preview and html sandbox

[waleedlatif1]

Summary

• Replaced the hardcoded domain allowlist in `img-src` with `https:` — allows users to embed any HTTPS image in markdown files without CSP violations
• Updated HTML preview sandbox CSP from `img-src data: blob:` to `img-src 'self' https: data: blob:` — enables external images and Sim-hosted files to render in HTML previews
• Sim files (`/api/files/serve/...`) work via `'self'` with automatic cookie-based auth; no extra plumbing needed

Type of Change

• Bug fix

Testing

Tested manually — external images now render in markdown preview; all 25 CSP unit tests pass

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		May 2, 2026 1:32am

[cursor]

PR Summary

Medium Risk
Broadens img-src to allow all https: image sources, which reduces CSP protection against unwanted third-party content/trackers if untrusted HTML/markdown is rendered. Change is localized to CSP generation but affects all pages using the main policy.

Overview
Updates the main Content Security Policy image allowlist to permit loading images from any https: origin.

This replaces the previous hardcoded img-src domain list (and related env-derived S3/brand URL hosts) with a simplified ['self', 'data:', 'blob:', 'https:'] for both build-time (buildTimeCSPDirectives) and runtime (generateRuntimeCSP()) CSP generation.

^{Reviewed by Cursor Bugbot for commit 4c08519. Configure here.}

[greptile-apps]

Greptile Summary

This PR simplifies the img-src CSP directive from a hardcoded domain allowlist to 'self' data: blob: https:, allowing any HTTPS image source in the main application. The change removes previously dynamic per-S3-bucket domains, brand logo/favicon URLs, and the hosted-only GTM/Analytics entries from img-src, all of which are now redundant under the https: wildcard. The brandFaviconDomains variable is also correctly removed from generateRuntimeCSP() since it was only ever consumed by img-src.

Confidence Score: 5/5

Safe to merge — the csp.ts changes are coherent and the intentional policy broadening is well-scoped to img-src only.

Single file changed, no logic errors or dead variables introduced. The https: wildcard for img-src is a deliberate and documented trade-off; connect-src, script-src, and all other directives remain unchanged and tight.

No files require special attention.

Important Files Changed

Filename	Overview
apps/sim/lib/core/security/csp.ts	img-src simplified to https: wildcard; dynamic S3/brand domain entries and brandFaviconDomains variable correctly removed; brandLogoDomains still present and correctly consumed by connect-src

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
A[Browser requests image] --> B{img-src CSP check}
B -- "Before: domain allowlist" --> C["'self' data: blob:\nhttps://*.googleusercontent.com\nhttps://*.s3.amazonaws.com\n... 10+ more domains"]
B -- "After: https wildcard" --> D["'self' data: blob: https:"]
C --> E{Matches allowlist?}
D --> F{Is HTTPS?}
E -- Yes --> G[Image loads]
E -- No --> H[CSP violation - blocked]
F -- Yes --> G
F -- No --> H
G --> I[Rendered in markdown / app]

Loading

_{Reviews (4): Last reviewed commit: "fix(csp): revert html preview img-src to..." | Re-trigger Greptile}

[waleedlatif1]

@greptile

[waleedlatif1]

@cursor review

[waleedlatif1]

@greptile

[waleedlatif1]

@cursor review

[waleedlatif1]

@greptile

[waleedlatif1]

@cursor review

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 7a18f1f. Configure here.}

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 4c08519. Configure here.}