KaTeX \htmlData does not validate attribute names
Impact
KaTeX users who render untrusted mathematical expressions with renderToString could encounter malicious input using \htmlData that runs arbitrary JavaScript, or generate invalid HTML.
Patches
Upgrade to KaTeX v0.16.21 to remove this vulnerability.
Workarounds
- Avoid use of or turn off the
trustoption, or set it to forbid\htmlDatacommands. - Forbid inputs containing the substring
"\\htmlData". - Sanitize HTML output from KaTeX.
Details
\htmlData did not validate its attribute name argument, allowing it to generate invalid or malicious HTML that runs scripts.
For more information
If you have any questions or comments about this advisory:
- Open an issue or security advisory in the KaTeX repository
- Email us at katex-security@mit.edu
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | katex | >= 0.12.0, < 0.16.21 | 0.16.21 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L- Weakness (CWE)
CWE-116, CWE-79- Platform
- npm
- Package
katex- Disclosed
- 17.01.2025
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-cg87-wmx4-v546 - CC BY 4.0
Vulnerability history: katex
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 6
- First → latest
- 03.2024 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 5
- Low 1
Disclosures per year
- 2024: 4
- 2025: 1
- 2026: 1
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KaTeX \htmlData does not validate attribute names this entry
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