CVE-2025-3033: Mozilla Firefox

High severity, CVSS 7.7. EPSS: 0.2% chance of exploitation in the next 30 days.

After selecting a malicious Windows `.url` shortcut from the local filesystem, an unexpected file could be uploaded. *This bug only affects Firefox on Windows. Other operating systems are unaffected.*. This vulnerability was fixed in Firefox 137 and Thunderbird 137.

Affected products

• Mozilla Firefox: before 137.0 (fixed in 137.0)
• Mozilla Thunderbird: before 137.0 (fixed in 137.0)

Published 2025-04-01. Last modified 2026-09-30.