CVE-2021-23983: Mozilla Firefox

Medium severity, CVSS 6.5. EPSS: 0.7% chance of exploitation in the next 30 days.

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)

Published 2021-03-31. Last modified 2026-06-17.