CVE-2021-23974

MEDIUM 6.1CVE-2021-23974 · Published 26/02/2021 · updated 17/06/2026

In short

CVE-2021-23974 is a MEDIUM (CVSS 6.1) vulnerability affecting firefox (mozilla).
Chance of exploitation in the next 30 days (EPSS): 0.75%, higher than 55.2% of all vulnerabilities.
Fix: update to 86.0 or later.

Package	Affected versions	Patched versions
firefox mozilla	`< 86.0`	`86.0`

Description

The DOMParser API did not properly process '<noscript>' elements for escaping. This could be used as an mXSS vector to bypass an HTML Sanitizer. This vulnerability affects Firefox < 86.

References

bugzilla.mozilla.org/buglist.cgi · Issue Tracking
security.gentoo.org/glsa/202104-10 · Third Party Advisory
mozilla.org/security/advisories/mfsa2021-07 · Release Notes

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Package

Affected versions

Patched versions

firefox

mozilla

< 86.0

86.0

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