CVE-2026-12318 addresses incorrect boundary conditions in the NSS Libraries component within Mozilla Firefox. This flaw could potentially lead to memory safety issues or other security impacts. The vulnerability affects Firefox versions prior to 152 and was resolved in Firefox 152. Mozilla's official advisory groups this vulnerability among multiple high-impact security fixes in Firefox 152 and Thunderbird 152. The advisory confirms the fix and provides detailed references to the underlying bugs. No active exploitation has been observed.

The vulnerability has a CVSS v3.1 score of 7.3 (high), indicating it can impact confidentiality, integrity, and availability with network attack vector, low attack complexity, no privileges required, and no user interaction needed. While the direct exploitability is not confirmed, the incorrect boundary conditions could lead to memory corruption or other security issues if triggered. No known exploits in the wild have been reported for this vulnerability.

An official fix is available and was released in Mozilla Firefox version 152. Users and administrators should update affected Firefox installations to version 152 or later to remediate this vulnerability. The vendor advisory confirms the fix and no additional mitigations are required beyond applying the update.