CVE-2026-74961: Mozilla Firefox

Critical severity, CVSS 9.1. EPSS: 0.4% chance of exploitation in the next 30 days.

Side-channel in the Web Audio component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

Affected products

• Mozilla Firefox: before 153.1.0 (fixed in 153.1.0)
• Mozilla Thunderbird: before 153.1.0 (fixed in 153.1.0)

Published 2026-08-18. Last modified 2026-08-20.