CVE-2025-8039: Mozilla Firefox

High severity, CVSS 8.1. EPSS: 0.3% chance of exploitation in the next 30 days.

In some cases search terms persisted in the URL bar even after navigating away from the search page. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.

Affected products

• Mozilla Firefox: before 140.1 (fixed in 140.1); before 141.0 (fixed in 141.0)
• Mozilla Thunderbird: before 140.1 (fixed in 140.1); before 141.0 (fixed in 141.0)

Published 2025-07-22. Last modified 2026-10-05.