CVE-2026-2767 describes a use-after-free vulnerability in the JavaScript WebAssembly component of Mozilla Firefox. Use-after-free (CWE-416) vulnerabilities occur when a program continues to use a pointer after the memory it points to has been freed, potentially leading to memory corruption and arbitrary code execution. This specific vulnerability was fixed in Firefox 148 and Firefox ESR 140.8 as part of a broader set of memory safety bugs addressed by Mozilla. The CVSS 3.1 base score of 8.8 reflects a network attack vector with low attack complexity, no privileges required, but requiring user interaction, and impacts confidentiality, integrity, and availability at a high level. The vendor advisory confirms the fix and recommends updating to the patched versions.

Successful exploitation of this use-after-free vulnerability could allow an attacker to execute arbitrary code, cause a denial of service, or otherwise compromise the confidentiality, integrity, and availability of the affected system. The vulnerability affects the WebAssembly component of Firefox, which is widely used for running compiled code in the browser, thus potentially impacting many users. However, there are no known exploits in the wild at the time of this advisory.

Mozilla has released official fixes for this vulnerability in Firefox 148 and Firefox ESR 140.8. Users and administrators should update affected Firefox installations to these versions or later to remediate the vulnerability. Since this is a client-side application, applying the official update is the recommended and effective mitigation. No additional temporary workarounds or mitigations are indicated by the vendor advisory.