Buffer overflow in Mozilla Firefox
CVE-2026-2807
Memory safety bugs present in Firefox 147 and Thunderbird 147. 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 148 and Thunderbird 148.
Vulnerability class: Buffer Overflow
EPSS: 0.002 (15.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Mozilla Firefox — versions 148
- Mozilla Thunderbird — versions 148
Weakness classification (CWE)
References
- security@mozilla.org (Broken Link)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-2807?
- CVE-2026-2807 is a critical-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2026-02-24.
- How severe is CVE-2026-2807?
- Critical severity. CVSS v3 base score is 9.8 out of 10.