CVE-2026-12310 is a memory safety bug in Mozilla Firefox identified and fixed in Firefox 152 and Firefox ESR 140.12. It is part of a broader set of memory safety vulnerabilities fixed in these versions, some of which showed evidence of memory corruption that could be exploited for arbitrary code execution. The vendor advisories confirm that these vulnerabilities were present in Firefox 151, Firefox ESR 140.11, and earlier versions, and were remediated in the stated fixed versions. No known exploits in the wild have been reported. The vendor advisories provide detailed references to multiple related bugs and confirm the high impact of these memory safety issues.

The vulnerability involves memory safety bugs that could lead to memory corruption. With sufficient effort, these could have been exploited to execute arbitrary code on affected systems. This poses a high security risk as it could allow attackers to compromise the confidentiality, integrity, and availability of the affected Firefox browser. No active exploitation has been reported, but the potential impact is significant.

Mozilla has released official fixes for this vulnerability in Firefox 152 and Firefox ESR 140.12. Users and administrators should update to these versions or later to remediate the issue. Since this is not a cloud service, remediation requires applying the vendor-provided updates. Patch status is confirmed by the vendor advisories linked. No additional mitigation actions are required beyond applying the official updates.