CVE-2025-11715: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 0.3% chance of exploitation in the next 30 days.

Memory safety bugs present in Firefox ESR 140.3, Thunderbird ESR 140.3, Firefox 143 and Thunderbird 143. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 144, Firefox ESR 140.4, Thunderbird 144, and Thunderbird 140.4.

Affected products

• Mozilla Firefox: before 140.4.0 (fixed in 140.4.0); before 144.0 (fixed in 144.0)
• Mozilla Thunderbird: before 140.4.0 (fixed in 140.4.0); before 144.0 (fixed in 144.0)

Published 2025-10-14. Last modified 2026-06-17.