CVE-2026-2447: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 0.6% chance of exploitation in the next 30 days.

Heap buffer overflow in libvpx. This vulnerability was fixed in Firefox 147.0.4, Firefox ESR 140.7.1, Firefox ESR 115.32.1, Thunderbird 140.7.2, and Thunderbird 147.0.2.

Affected products

• Mozilla Firefox: before 115.32.1 (fixed in 115.32.1); before 147.0.4 (fixed in 147.0.4); from 116.0, before 140.7.1 (fixed in 140.7.1)
• Mozilla Thunderbird: before 140.7.2 (fixed in 140.7.2); from 141.0, before 147.0.2 (fixed in 147.0.2)

Published 2026-02-16. Last modified 2026-07-15.