fix(deps): update dependency mermaid to v10.9.4 [security]

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This PR contains the following updates:

Package	Change	Age	Confidence
mermaid	10.9.1 -> 10.9.4

GitHub Vulnerability Alerts

CVE-2025-54881

Summary

In the default configuration of mermaid 11.9.0, user supplied input for sequence diagram labels is passed to innerHTML during calculation of element size, causing XSS.

Details

Sequence diagram node labels with KaTeX delimiters are passed through calculateMathMLDimensions. This method passes the full label to innerHTML which allows allows malicious users to inject arbitrary HTML and cause XSS when mermaid-js is used in it's default configuration (with KaTeX support enabled).

The vulnerability lies here:

export const calculateMathMLDimensions = async (text: string, config: MermaidConfig) => {
  text = await renderKatex(text, config);
  const divElem = document.createElement('div');
  divElem.innerHTML = text; // XSS sink, text has not been sanitized.
  divElem.id = 'katex-temp';
  divElem.style.visibility = 'hidden';
  divElem.style.position = 'absolute';
  divElem.style.top = '0';
  const body = document.querySelector('body');
  body?.insertAdjacentElement('beforeend', divElem);
  const dim = { width: divElem.clientWidth, height: divElem.clientHeight };
  divElem.remove();
  return dim;
};

The calculateMathMLDimensions method was introduced in 5c69e5fdb004a6d0a2abe97e23d26e223a059832 two years ago, which was released in Mermaid 10.9.0.

PoC

Render the following diagram and observe the modified DOM.

sequenceDiagram
    participant A as Alice<img src="x" onerror="document.write(`xss on ${document.domain}`)">$$\\text{Alice}$$
    A->>John: Hello John, how are you?
    Alice-)John: See you later!

Here is a PoC on mermaid.live: https://mermaid.live/edit#pako:eNpVUMtOwzAQ_BWzyoFKaRTyaFILiio4IK7ckA-1km1iKbaLY6spUf4dJ0AF68uOZ2dm7REqXSNQ6PHDoarwWfDGcMkUudaJGysqceLKkj3hPdl3osJ7IRvSm-qBwcCAaIXGaONRrSsnUdnobITF28PQ954lwXglai25UNNhxWAXBMyXxcGOi-3kL_5k79e73atuFSUv2HWazH1IWn0m3CC5aPf4b3p2WK--BW-4DJCOWzQ3TM0HQmiMqIFa4zAEicZv4iGMsw0D26JEBtS3NR656ywDpiYv869_11r-Ko12TQv0yLveI3eqfcjP111HUNVonrRTFuhdsVgAHWEAmuRxlG7SuEzKMi-yJAnhAjTLIk_EcbFJtuk2y9MphM8lM47KIp--AOZghtU

Impact

XSS on all sites that use mermaid and render user supplied diagrams without further sanitization.

Remediation

The value of the text argument for the calculateMathMLDimensions method needs to be sanitized before getting passed on to innerHTML.

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Release Notes

mermaid-js/mermaid (mermaid)

v10.9.4

Compare Source

This release backports the fix for GHSA-7rqq-prvp-x9jh from v11.10.0, preventing a potential XSS attack in labels in sequence diagrams.

See: 9d68517 (on main branch)
See: 7509b06 (backported commit)

Full Changelog: mermaid-js/mermaid@v10.9.3...v10.9.4

v10.9.3

Compare Source

Updates the bundled version of dependencies in the following files:

• dist/mermaid.min.js
• dist/mermaid.js
• dist/mermaid.esm.mjs
• dist/mermaid.esm.min.mjs

If you are not using these files (e.g. you are using the default NPM export of mermaid, e.g. import mermaid from 'mermaid', or you are using dist/mermaid.core.mjs), this release is identical to v10.9.2.

This is to avoid potential security issues in KaTeX and DOMPurify, see:

• GHSA-mmhx-hmjr-r674
• GHSA-64fm-8hw2-v72w
• GHSA-cvr6-37gx-v8wc
• GHSA-f98w-7cxr-ff2h
• GHSA-3wc5-fcw2-2329

These dependencies have already been updated in v11.0.0.

Changelog

Chore

• Updates the bundled version of KaTeX to 0.16.11 (2bedd0e)
• Updates the bundled version of DOMPurify to 3.1.6 (92a07ff)

Full Changelog: mermaid-js/mermaid@v10.9.2...v10.9.3

v10.9.2

Compare Source

This release back-ports #​5914 to the v10 release line to fix #​5904 (an incompatibility between mermaid and DOMPurify v3.1.7)

Patch Changes

• #​5914 402abdf [10] fix: ban version v3.1.7 of DOMPurify

Full Changelog: mermaid-js/mermaid@v10.9.1...v10.9.2

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