GHSA-m64q-4jqh-f72f
MEDIUMStored Cross-site Scripting (XSS) in excalidraw's web embed component
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
@excalidraw/excalidraw📦@excalidraw/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
Summary
A stored XSS vulnerability in Excalidraw's web embeddable component. This allows arbitrary JavaScript to be run in the context of the domain where the editor is hosted.
Poc
Inserting an embed with the below url (can be copy/pasted onto canvas to insert as embed) will log 42 to the console:
https://gist.github.com/vv=v<script>console.log(42)</script>
Details
There were two vectors. One rendering untrusted string as iframe's srcdoc without properly sanitizing against HTML injection. Second by improperly sanitizing against attribute HTML injection. This in conjunction with allowing allow-same-origin sandbox flag (necessary for several embeds) resulted in the XSS.
Former was fixed by no longer rendering unsafe srcdoc content verbatim, and instead strictly parsing the supplied content and constructing the srcdoc manually. The latter by sanitizing properly.
The allow-same-origin flag is now also set only in cases that require it, following the principle of least privilege.
Impact
This is a cross site scripting vulnerability, for more information, please see: https://portswigger.net/web-security/cross-site-scripting
Two npm @excalidraw/excalidraw stable version releases were affected (0.16.x, 0.17.x), and both are now patched.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @excalidraw/excalidraw | ≥ 0.16.0&&< 0.16.4 | 0.16.4 |
| 📦npm | @excalidraw/excalidraw | ≥ 0.17.0&&< 0.17.6 | 0.17.6 |
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 0.16.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m64q-4jqh-f72f 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-m64q-4jqh-f72f 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-m64q-4jqh-f72f. 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-m64q-4jqh-f72f in your dependencies?
O3 detects GHSA-m64q-4jqh-f72f across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.