CVE-2022-28281: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 2.6% chance of exploitation in the next 30 days.

If a compromised content process sent an unexpected number of WebAuthN Extensions in a Register command to the parent process, an out of bounds write would have occurred leading to memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 91.8, Firefox < 99, and Firefox ESR < 91.8.

Affected products

• Mozilla Firefox: before 99.0 (fixed in 99.0)
• Mozilla Firefox ESR: before 91.8 (fixed in 91.8)
• Mozilla Thunderbird: before 91.8 (fixed in 91.8)

Published 2022-12-22. Last modified 2026-06-17.