How severe is CVE-2025-23207?

CVE-2025-23207 has a CVSS score of 6.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2025-23207?

CVE-2025-23207 affects the following packages: katex (npm). Ecosystems affected: npm.

How do I fix CVE-2025-23207?

Update katex to 0.16.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-23207 is resolved across your whole dependency graph.

How do I detect CVE-2025-23207 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for katex, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-23207 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2025-23207 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-23207 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-23207?

CVE-2025-23207 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 35th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-23207?

CVE-2025-23207 is classified as CWE-116 (CWE-116), Cross-site Scripting (XSS) (CWE-79). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2025-23207 published, and has it been updated?

CVE-2025-23207 was published on January 17, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

CVE-2025-23207 — katex

MEDIUMFix: KaTeX/KaTeX@ff28995

CVE-2025-23207 is a medium-severity (CVSS 6.3) CWE-116 vulnerability in katex. A fix is available for katex — see the affected versions and patch details below.

\htmlData does not validate attribute names in KaTeX

Also known asGHSA-cg87-wmx4-v546

Published

Jan 17, 2025

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-23207.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs35th percentile — riskier than 35% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

3Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

katexnpm

42.3Mdownloads / week

Description

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 trust option, or set it to forbid \htmlData commands.
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 [email protected]

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`katex`	≥ 0.12.0&&< 0.16.21	0.16.21`npm install katex@0.16.21`

Affected Products

1 product · 1 configurations

Application

katexkatex

≥ 0.12.0 && < 0.16.21

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for katex, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update katex to 0.16.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-23207 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Workaround published by Red Hat

Users unable to upgrade should turn off the `trust` option or set it to forbid `\htmlData` commands, forbid inputs containing the substring `"\\htmlData"` and sanitize HTML output from KaTeX.

Source: Red Hat security advisory for CVE-2025-23207 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat OpenShift Dev Spaces 3 Containers	`devspaces/code-rhel9:3.19-20`	RHSA-2025:2753

Frequently Asked Questions

### 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 `trust` option, or set it to forbid `\htmlData` commands. - 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 scr