CVE-2026-12311

Vulnerability

CVE-2026-12311 is an information disclosure and sandbox escape vulnerability in the Security: Process Sandboxing component of Mozilla Firefox. The flaw allows an attacker to bypass the sandbox restrictions and disclose sensitive information. The vulnerability affects Firefox versions prior to 152 and Firefox ESR versions prior to 140.12 [1][2].

Exploitation

An attacker with the ability to execute code within a sandboxed process could exploit this vulnerability to escape the sandbox. The exact exploitation steps are not detailed in the available references, but the vulnerability is rated high severity, indicating a realistic attack vector.

Impact

Successful exploitation allows an attacker to escape the Firefox process sandbox, leading to information disclosure and potential further compromise of the host system. The attacker gains the ability to access data or execute code outside the sandbox, bypassing security boundaries.

Mitigation

The vulnerability is fixed in Firefox 152 and Firefox ESR 140.12, both released on June 16, 2026 [1][2]. Users should update to these versions or later. No workarounds are documented.