CVE-2025-4082: Mozilla Firefox

Medium severity, CVSS 5.9. EPSS: 0.5% chance of exploitation in the next 30 days.

Modification of specific WebGL shader attributes could trigger an out-of-bounds read, which, when chained with other vulnerabilities, could be used to escalate privileges. *This bug only affects Thunderbird for macOS. Other versions of Thunderbird are unaffected.*. This vulnerability was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.

Affected products

• Mozilla Firefox: before 115.23 (fixed in 115.23); before 138.0 (fixed in 138.0); from 128.0, before 128.10 (fixed in 128.10)
• Mozilla Thunderbird: before 128.10.0 (fixed in 128.10.0); before 138.0 (fixed in 138.0)

Published 2025-04-29. Last modified 2026-10-05.