fix(media-embed): remove ReDoS-prone regexes in host-gated providers

[waleedlatif1]

Summary

• Fixes 3 CodeQL High js/polynomial-redos alerts on packages/utils/src/media-embed.ts (introduced by feat(rich-markdown-editor): live media embeds + shared embed detection util #5290, now in staging)
• The YouTube, Facebook, and Giphy branches used unbounded .* inside unanchored regexes. Even with the hostname gate, a crafted valid-host URL with a long path/query (e.g. https://facebook.com/ + 100k junk chars, no /videos/) triggers O(n²) backtracking — a client-side hang since getEmbedInfo runs during note rendering + editor decoration (a crafted link in shared content could freeze other users' tabs)
• Replaced each with bounded extraction off the parsed URL (parsed.pathname / parsed.searchParams), so there is no .* left in these branches. No change to which links match

Detail

• YouTube: youtu.be → first path segment; watch → searchParams.get('v'); embed → anchored /^\/embed\/([^/?]+)/; result validated with /^[a-zA-Z0-9_-]{11}$/
• Facebook: detect video via /\/videos\/\d+/ on the pathname (fb.watch via anchored segment) instead of facebook.com/.*/videos/
• Giphy: take the trailing hyphen token of the /gifs|embed/ path segment ([^/]+ + split('-').pop()), validated [a-zA-Z0-9]+

Type of Change

• Bug fix (security — ReDoS)

Testing

• media-embed.test.ts: existing cases pass; added coverage for extra YouTube query params, Facebook/fb.watch, and Giphy slug extraction (10 tests). tsc clean.

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)

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Project	Deployment	Actions	Updated (UTC)
docs	Ready	Preview, Comment	Jul 1, 2026 1:15am

[cursor]

PR Summary

Medium Risk
Security fix in client-side URL parsing used during note rendering; logic is refactored but host gating and stricter id validation should preserve safe embed behavior.

Overview
Addresses CodeQL polynomial ReDoS in getEmbedInfo by replacing unbounded .* regex ID extraction on YouTube, Facebook/fb.watch, and Giphy with bounded reads from the parsed URL (pathname segments, searchParams, and short anchored path checks).

YouTube now pulls the video id from youtu.be path, /embed/ segment, or v query param and requires an 11-character id. Facebook treats links as video only when the pathname matches /videos/\d+ (or fb.watch’s single segment). Giphy takes the last hyphen token from the /gifs or /embed segment. Matching behavior is intended to stay the same; tests add cases for extra query params, non-video Facebook URLs, and slug-style Giphy links.

^{Reviewed by Cursor Bugbot for commit 64df33e. Configure here.}

[greptile-apps]

Greptile Summary

This PR removes ReDoS-prone media embed matching from host-gated providers. The main changes are:

• Parsed-URL extraction for YouTube, Facebook, and Giphy links.
• YouTube embed paths now take precedence over conflicting v query params.
• Tests for provider matching and key URL edge cases.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
packages/utils/src/media-embed.ts	Replaces risky provider regex matching with parsed pathname and query extraction.
packages/utils/src/media-embed.test.ts	Adds tests for YouTube precedence and provider-specific embed extraction.

_{Reviews (2): Last reviewed commit: "fix(media-embed): dispatch YouTube id by..." | Re-trigger Greptile}

[waleedlatif1]

@greptile

[waleedlatif1]

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^{Reviewed by Cursor Bugbot for commit 64df33e. Configure here.}