CVE-2026-74965: Mozilla Firefox

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

Privilege escalation in the Shell Integration component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Affected products

• Mozilla Firefox: before 140.14.0 (fixed in 140.14.0); before 154.0.0 (fixed in 154.0.0); version 153.0 only
• Mozilla Thunderbird: before 140.14.0 (fixed in 140.14.0); before 154.0 (fixed in 154.0); from 153.0, before 153.1.0 (fixed in 153.1.0)

Published 2026-08-18. Last modified 2026-08-21.