MathLive's Lack of Escaping of HTML allows for XSS

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS

• CVE-2025-29049: 0.63% estimated exploitation activity in the next 30 days; percentile 50.11 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Despite normal text rendering as LaTeX expressions, preventing XSS, the library also provides users with commands which may modify HTML, such as the \htmlData command, and the lack of escaping leads to XSS. Details Overall in the code, other than in the test folder, no functions escaping HTML can be seen. PoC 1. Go to https://cortexjs.io/mathlive/demo/ 2. Paste either \htmlData{<img/onerror=alert(1)"src=}{} or \htmlData{x=" <img/onerror=alert(1) src}{} in the LaTeX textarea. Impact MathLive users who render untrusted mathematical expressions could encounter malicious input using \htmlData that runs arbitrary JavaScript, or generate invalid HTML.

Published by the source

21 Jan 2025, 21:17 UTC

Last modified by the source

8 Jul 2026, 07:27 UTC

Source last checked

26 Oct 2026, 12:36 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-qwj6-q94f-8425

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-qwj6-q94f-8425

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# Patch Next advisory brief: CVE-2025-29049

Advisory: MathLive's Lack of Escaping of HTML allows for XSS
IDs: CVE-2025-29049, GHSA-qwj6-q94f-8425
Record: https://patchnext.com/advisories/cve-2025-29049 (revision 2, source checked 26 Oct 2026, 12:36 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mathlive 0.104.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm mathlive: affected <= 0.103.0; fixed in 0.104.0

## Suggested inspection (read-only)
- `npm ls mathlive --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mathlive.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-qwj6-q94f-8425 (OSV record GHSA-qwj6-q94f-8425 lists affected ranges: npm mathlive >=0 <0.104.0 (fixed))
- Verified: https://github.com/advisories/GHSA-qwj6-q94f-8425 (GitHub-reviewed advisory GHSA-qwj6-q94f-8425 lists affected ranges: npm mathlive >=0 <=0.103.0)

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