CSRF in Mozilla Firefox
CVE-2025-4088
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.
Vulnerability class: CSRF (Cross-Site Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (6.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 6.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Mozilla Firefox — versions 138
- Mozilla Thunderbird — versions 138
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2025-28/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-31/ (Vendor Advisory)
Frequently asked questions
- What is CVE-2025-4088?
- CVE-2025-4088 is a medium-severity vulnerability in Mozilla Firefox, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2025-04-29.
- How severe is CVE-2025-4088?
- Medium severity. CVSS v3 base score is 6.5 out of 10.