Summary
Excalidraw vulnerable to XSS via Mermaid sequence diagram labels (KaTeX rendering)
Workarounds
None.
Resources
- Upstream Mermaid advisory: https://github.com/mermaid-js/mermaid/security/advisories/GHSA-7rqq-prvp-x9jh
- CVE-2025-54881
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).
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
- 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.
Frequently Asked Questions
- What is GHSA-39H7-PWV7-RC3X? GHSA-39H7-PWV7-RC3X is a medium-severity cross-site scripting (XSS) vulnerability in @excalidraw/excalidraw (npm), affecting versions = 0.18.0. It is fixed in 0.18.1, 1.1.3. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- Which packages are affected by GHSA-39H7-PWV7-RC3X?
@excalidraw/excalidraw(npm) (versions = 0.18.0)@excalidraw/mermaid-to-excalidraw(npm) (versions >= 0.3.0, < 1.1.3)
- Is there a fix for GHSA-39H7-PWV7-RC3X? Yes. GHSA-39H7-PWV7-RC3X is fixed in 0.18.1, 1.1.3. Upgrade to this version or later.
- Is GHSA-39H7-PWV7-RC3X exploitable, and should I be worried? Whether GHSA-39H7-PWV7-RC3X is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-39H7-PWV7-RC3X is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-39H7-PWV7-RC3X?
- Upgrade
@excalidraw/excalidrawto 0.18.1 or later - Upgrade
@excalidraw/mermaid-to-excalidrawto 1.1.3 or later
- Upgrade