CVE-2022-38478: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 0.9% chance of exploitation in the next 30 days.

Members the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 103, Firefox ESR 102.1, and Firefox ESR 91.12. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 102.2, Thunderbird < 91.13, Firefox ESR < 91.13, Firefox ESR < 102.2, and Firefox < 104.

Affected products

• Mozilla Firefox: before 104.0 (fixed in 104.0); from 102.0, before 102.2 (fixed in 102.2)
• Mozilla Firefox ESR: before 91.13 (fixed in 91.13)
• Mozilla Thunderbird: before 91.13 (fixed in 91.13); from 102.0, before 102.2 (fixed in 102.2)

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