CVE-2025-10527: Mozilla Firefox

High severity, CVSS 7.1. EPSS: 0.3% chance of exploitation in the next 30 days.

Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird 140.3.

Affected products

• Mozilla Firefox: before 140.3.0 (fixed in 140.3.0); up to and including 143.0
• Mozilla Thunderbird: before 140.3.0 (fixed in 140.3.0); from 141.0, before 143.0 (fixed in 143.0)

Published 2025-09-16. Last modified 2026-06-17.