CVE-2026-6761: Mozilla Firefox

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

Privilege escalation in the Networking component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

Affected products

• Mozilla Firefox: before 140.10.0 (fixed in 140.10.0); before 150.0 (fixed in 150.0)
• Mozilla Thunderbird: before 140.10.0 (fixed in 140.10.0)

Published 2026-04-21. Last modified 2026-06-17.