CVE-2026-2797: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 0.5% chance of exploitation in the next 30 days.

Use-after-free in the JavaScript: GC component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

Affected products

• Mozilla Firefox: before 148.0 (fixed in 148.0)
• Mozilla Thunderbird: before 148.0 (fixed in 148.0)

Published 2026-02-24. Last modified 2026-07-15.