CVE-2021-23980

Name: CVE-2021-23980
Creator: NVD / NIST
Published: 2023-02-16T22:15:10.713+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.48%

Last modified Jun 17, 2026

CVE-2021-23980 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. A mutation XSS affects users calling bleach.clean with all of: svg or math in the allowed tags p or br in allowed tags style, title, noscript, script, textarea, noframes, iframe, or xmp in allowed tags the keyword argument strip_comments=False Note: none of the above tags are in the default allowed tags and strip_comments defaults to True.. EPSS estimates a 0.48% chance of exploitation in the next 30 days.

Description

A mutation XSS affects users calling bleach.clean with all of: svg or math in the allowed tags p or br in allowed tags style, title, noscript, script, textarea, noframes, iframe, or xmp in allowed tags the keyword argument strip_comments=False Note: none of the above tags are in the default allowed tags and strip_comments defaults to True.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

0.48%

37.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Mozilla	Bleach	< 3.3.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=CVE-2021-23980Exploit, Issue Tracking
https://github.com/mozilla/bleach/security/advisories/GHSA-vv2x-vrpj-qqpqVendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=CVE-2021-23980Exploit, Issue Tracking
https://github.com/mozilla/bleach/security/advisories/GHSA-vv2x-vrpj-qqpqVendor Advisory

Timeline

Published: Feb 16, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-23980?

How severe is CVE-2021-23980?

CVE-2021-23980 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.48% probability of exploitation in the next 30 days.

How do I fix CVE-2021-23980?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-23980?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST