CVE-2026-92054: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 0.2% chance of exploitation in the next 30 days.

Privilege escalation in the Memory component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.

Affected products

• Mozilla Firefox: before 153.3.0 (fixed in 153.3.0); from 154.0.0, before 156.0.0 (fixed in 156.0.0)
• Mozilla Thunderbird: before 153.3.0 (fixed in 153.3.0); from 154.0, before 156.0 (fixed in 156.0)

Published 2026-09-15. Last modified 2026-10-05.