CVE-2021-23983

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-03-31 · updated 2026-06-17
Weakness: CWE-787

Description

By causing a transition on a parent node by removing a CSS rule, an invalid property for a marker could have been applied, resulting in memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 87.

Affected products

Mozilla Firefox: before 87.0 — fixed in 87.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 87.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1692684
https://www.mozilla.org/security/advisories/mfsa2021-10/
https://bugzilla.mozilla.org/show_bug.cgi?id=1692684
https://www.mozilla.org/security/advisories/mfsa2021-10/

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