CVE-2021-29952: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

When Web Render components were destructed, a race condition could have caused undefined behavior, and we presume that with enough effort may have been exploitable to run arbitrary code. This vulnerability affects Firefox < 88.0.1 and Firefox for Android < 88.1.3.

Affected products

• Mozilla Firefox: before 88.0.1 (fixed in 88.0.1); before 88.1.3 (fixed in 88.1.3)

Published 2021-06-24. Last modified 2026-06-17.