CVE-2025-6426: Mozilla Firefox

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

The executable file warning did not warn users before opening files with the `terminal` extension. *This bug only affects Firefox for macOS. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

Affected products

• Mozilla Firefox: before 128.12.0 (fixed in 128.12.0); before 140.0 (fixed in 140.0)

Published 2025-06-24. Last modified 2026-10-05.