CVE-2026-2786 is a use-after-free vulnerability identified in the JavaScript Engine component of Mozilla Firefox. Use-after-free issues occur when a program continues to use a pointer after the memory it points to has been freed, potentially leading to memory corruption. This vulnerability was fixed in Firefox 148 and Firefox ESR 140.8 as part of a comprehensive security update addressing multiple high-impact bugs. The CVSS 3.1 base score is 8.8, indicating high severity with network attack vector, low attack complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability. Mozilla’s official advisories confirm the availability of patches and recommend updating to the fixed versions.

The vulnerability could allow an attacker to exploit memory corruption in the JavaScript Engine, potentially leading to arbitrary code execution, information disclosure, or denial of service. The high CVSS score (8.8) reflects the critical nature of the impact on confidentiality, integrity, and availability. However, no active exploitation in the wild has been reported at the time of the advisory.

Mozilla has released official fixes for this vulnerability in Firefox 148 and Firefox ESR 140.8. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation steps are required beyond applying the official patches as per Mozilla’s advisory.