CVE-2025-23207: katex Improper Encoding — Fix

Description

KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web. KaTeX users who render untrusted mathematical expressions with `renderToString` could encounter malicious input using `\htmlData` that runs arbitrary JavaScript, or generate invalid HTML. Users are advised to upgrade to KaTeX v0.16.21 to remove this vulnerability. Users unable to upgrade should avoid use of or turn off the `trust` option, or set it to forbid `\htmlData` commands, forbid inputs containing the substring `"\\htmlData"` and sanitize HTML output from KaTeX.

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CVSS v3.1 Score

6.3

MEDIUM

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

Weakness Type (CWE)

CWE-116 CWE-116

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
katex	katex	0.12.0 — 0.16.21

References

Advisories & Patches

https://github.com/KaTeX/KaTeX/commit/ff289955e81aab89086eef09254cbf88573d415c

Other References

https://github.com/KaTeX/KaTeX/security/advisories/GHSA-cg87-wmx4-v546

Frequently Asked Questions

What is CVE-2025-23207? +

KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web. KaTeX users who render untrusted mathematical expressions with `renderToString` could encounter malicious input using `\htmlData` that runs arbitrary JavaScript, or generate invalid HTML. Users are advised to upgrade to KaTeX v0.16.21 to remove this vulnerability. Users unable to upgrade should avoid use of or turn off the `trust` option, or set it to forbid `\htmlData` commands, forbid inputs containing the substring `"\\htmlData"` and sanitize HTML output from KaTeX. It has a CVSS v3.1 base score of 6.3 (MEDIUM).

How severe is CVE-2025-23207? +

CVE-2025-23207 has a CVSS v3.1 score of 6.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-23207? +

CVE-2025-23207 affects products from katex, specifically: katex. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-23207? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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