Buffer overflow in Mozilla Firefox
CVE-2025-1016
Memory safety bugs present in Firefox 134, Thunderbird 134, Firefox ESR 115.19, Firefox ESR 128.6, Thunderbird 115.19, and Thunderbird 128.6. 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 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.
Vulnerability class: Buffer Overflow
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.006 (46.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Mozilla Firefox — versions 115.20, 128.7, 135
- Mozilla Thunderbird — versions 128.7, 135
Weakness classification (CWE)
Public proof-of-concept exploits
References
- bugzilla.mozilla.org/buglist.cgi (Broken Link)
- www.mozilla.org/security/advisories/mfsa2025-07/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-08/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-09/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-10/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-11/ (Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-1016?
- CVE-2025-1016 is a critical-severity vulnerability in Mozilla Firefox, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2025-02-04.
- How severe is CVE-2025-1016?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2025-1016 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.