CVE-2025-4088: Mozilla Firefox

Medium severity, CVSS 6.5. EPSS: 0.2% chance of exploitation in the next 30 days.

A security vulnerability in Thunderbird allowed malicious sites to use redirects to send credentialed requests to arbitrary endpoints on any site that had invoked the Storage Access API. This enabled potential Cross-Site Request Forgery attacks across origins. 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.