CVE-2025-4085: Mozilla Firefox

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

An attacker with control over a content process could potentially leverage the privileged UITour actor to leak sensitive information or escalate privileges. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

Affected products

• Mozilla Firefox: before 138.0 (fixed in 138.0)
• Mozilla Thunderbird: before 138.0 (fixed in 138.0)

Published 2025-04-29. Last modified 2026-09-30.