GHSA-39h7-pwv7-rc3x
GHSA-39h7-pwv7-rc3x is a security vulnerability in @excalidraw/excalidraw. O3 Security confirms whether GHSA-39h7-pwv7-rc3x is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Excalidraw vulnerable to XSS via Mermaid sequence diagram labels (KaTeX rendering)
Real-World Exposure
@excalidraw/excalidraw📦@excalidraw/mermaid-to-excalidrawReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Impact
@excalidraw/[email protected] depends on a Mermaid conversion package version that resolves to a Mermaid release affected by CVE-2025-54881 / GHSA-7rqq-prvp-x9jh. User-supplied Mermaid sequence diagram labels could trigger XSS through Mermaid’s KaTeX label rendering path.
This is patched in @excalidraw/[email protected] by updating @excalidraw/mermaid-to-excalidraw to 2.2.2, which uses a patched Mermaid 11 release.
Moderate severity as this XSS requires manual user action - pasting unsafe Mermaid diagram into the Excalidraw editor. No semi-automated attack vector exists by default (such as accessing a link).
Patches
- Stable
@excalidraw/[email protected]is patched. - Unstable
@excalidraw/excalidraw@nexthas resolved to patched builds since@excalidraw/[email protected]on 2025-08-21. - Direct consumers of
@excalidraw/mermaid-to-excalidrawshould use1.1.3or later.
Workarounds
None.
Resources
- Upstream Mermaid advisory: https://github.com/mermaid-js/mermaid/security/advisories/GHSA-7rqq-prvp-x9jh
- CVE-2025-54881
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @excalidraw/excalidraw | ≥ 0.18.0&&< 0.18.1 | 0.18.1 |
| 📦npm | @excalidraw/mermaid-to-excalidraw | ≥ 0.3.0&&< 1.1.3 | 1.1.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @excalidraw/excalidraw. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @excalidraw/excalidraw to 0.18.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-39h7-pwv7-rc3x is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-39h7-pwv7-rc3x is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-39h7-pwv7-rc3x. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-39h7-pwv7-rc3x in your dependencies?
O3 detects GHSA-39h7-pwv7-rc3x across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.