CVE-2026-74952: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 0.4% chance of exploitation in the next 30 days.

Privilege escalation in the Application Update component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 153.2, and Thunderbird 153.2.

Affected products

• Mozilla Firefox: before 154.0.0 (fixed in 154.0.0)
• Mozilla Thunderbird: before 154.0 (fixed in 154.0)

Published 2026-08-18. Last modified 2026-09-01.