A mitigation bypass was discovered in a DOM security component of Mozilla Firefox. The flaw allows an attacker to circumvent the browser’s built‑in security restrictions and gain unintended access to privileged functionality. The impact of exploiting the vulnerability could result in unauthorized manipulation of page content or elevation of privileges within the browser context. The precise mechanics are not detailed, but the intended security boundary is clearly violated.

Mozilla Firefox users running versions prior to 151 and those on the ESR channel older than 140.11 are potentially affected. All other, newer releases contain the fix.

The EPSS score is not available and the vulnerability is not listed in the CISA KEV catalog, so the public exploitation probability is uncertain. No CVSS score is supplied, which limits severity assessment. Based on the description, the likely attack vector involves malicious web content that can be delivered through a compromised site or local file. Once executed, an attacker may bypass DOM‑level restrictions and carry out actions that the was designed to prevent. The combination of a security‑boundary violation and the absence of a known public exploit suggests the risk is noteworthy for organizations that rely on older Firefox versions.