CVE-2026-16400 is an information disclosure vulnerability affecting the DOM: Security component in Mozilla Firefox. The flaw could allow an attacker to access sensitive information improperly. Mozilla fixed this vulnerability in Firefox 153 as part of a security advisory that addressed multiple high-impact issues. The CVSS v3.1 base score is 7.5, indicating a high severity with network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to confidentiality. The vendor advisory confirms the fix is included in Firefox 153.

The vulnerability allows unauthorized disclosure of information within the DOM: Security component, potentially exposing sensitive data to remote attackers without requiring privileges or user interaction. There is no impact on integrity or availability. No known active exploitation has been reported.

Users and administrators should update Mozilla Firefox to version 153 or later to remediate this vulnerability. The vendor advisory confirms that the issue is fixed in Firefox 153. No additional mitigation actions are required once the update is applied.