Buffer overflow in Mozilla Firefox
CVE-2025-1943
Memory safety bugs present in Firefox 135 and Thunderbird 135. 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 136 and Thunderbird 136.
Vulnerability class: Buffer Overflow
EPSS: 0.004 (32.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H.
Affected products
- Mozilla Firefox — versions 136
- Mozilla Thunderbird — versions 136
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security@mozilla.org (Broken Link)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
Frequently asked questions
- What is CVE-2025-1943?
- CVE-2025-1943 is a high-severity vulnerability in Mozilla Firefox, classified under Heap-based Buffer Overflow. CVSS score: 8.2/10. Published 2025-03-04.
- How severe is CVE-2025-1943?
- High severity. CVSS v3 base score is 8.2 out of 10.
- Is CVE-2025-1943 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.