Buffer overflow in Mozilla Firefox
CVE-2025-5272
Memory safety bugs present in Firefox 138 and Thunderbird 138. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
Vulnerability class: Buffer Overflow
EPSS: 0.003 (20.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
Affected products
- Mozilla Firefox — versions 139
- Mozilla Thunderbird — versions 139
Weakness classification (CWE)
References
- security@mozilla.org (Broken Link)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org
Frequently asked questions
- What is CVE-2025-5272?
- CVE-2025-5272 is a high-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Write. CVSS score: 7.3/10. Published 2025-05-27.
- How severe is CVE-2025-5272?
- High severity. CVSS v3 base score is 7.3 out of 10.