CVE-2026-2807
Published: 24 February 2026
Summary
CVE-2026-2807 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked at the 15.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-2807 encompasses multiple memory safety bugs in Firefox 147 and Thunderbird 147, classified under CWE-787 (Out-of-bounds Write). These bugs demonstrated evidence of memory corruption, and Mozilla presumes that with sufficient effort, some could be exploited to execute arbitrary code. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), marking it as critical.
Remote attackers can exploit this vulnerability over the network with low attack complexity, without requiring user privileges or interaction. Successful exploitation would grant high-impact confidentiality, integrity, and availability consequences, potentially enabling arbitrary code execution on affected systems.
Mozilla addressed CVE-2026-2807 in Firefox 148 and Thunderbird 148. Detailed information is available in Mozilla Security Advisories MFSA2026-13 and MFSA2026-16, along with the associated Bugzilla bugs (1756056, 1999402, 2004872, 2006037, 2012855).
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8461
Vulnerability details
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…
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fixed in Firefox 148 and Thunderbird 148.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Memory corruption RCE in browser/email client (no auth/UI required) directly enables drive-by compromise of clients and exploitation for client-side code execution.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates timely remediation of flaws like memory safety bugs through patching to Firefox/Thunderbird 148, preventing exploitation.
Implements memory protections such as ASLR and DEP to minimize impact of memory corruption from out-of-bounds writes, hindering arbitrary code execution.
Requires monitoring security advisories like Mozilla's MFSA2026-13/16 to identify and address the CVE-2026-2807 vulnerability promptly.