Use After Free in Mozilla Firefox
CVE-2025-1931
It was possible to cause a use-after-free in the content process side of a WebTransport connection, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.
Vulnerability class: Use-After-Free
EPSS: 0.005 (39.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Mozilla Firefox — versions 115.21, 128.8, 136
- Mozilla Thunderbird — versions 128.8, 136
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security@mozilla.org (Issue Tracking)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-1931?
- CVE-2025-1931 is a high-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 7.5/10. Published 2025-03-04.
- How severe is CVE-2025-1931?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2025-1931 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.