CVE-2026-74973: Mozilla Firefox

Medium severity, CVSS 4.2. EPSS: 0.2% chance of exploitation in the next 30 days.

Race condition, use-after-free in the Graphics component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Affected products

• Mozilla Firefox: before 115.39.0 (fixed in 115.39.0); from 116.0, before 140.14.0 (fixed in 140.14.0); from 141.0, before 153.1.0 (fixed in 153.1.0)
• Mozilla Thunderbird: before 140.14.0 (fixed in 140.14.0); from 141.0, before 153.1.0 (fixed in 153.1.0)

Published 2026-08-18. Last modified 2026-08-19.