Grav CMS Critical 2FA Bypass Vulnerability Discovered

A critical security vulnerability, tracked as CVE-2026-62232, has been identified in the Grav CMS login plugin. This flaw allows unauthorized actors to bypass two-factor authentication (2FA) by exploiting a flaw in the regenerate2FASecret task, posing a significant risk to the integrity of affected installations.

What's at Risk

The vulnerability affects all versions of Grav prior to 2.0.4. Organizations running internet-facing instances of Grav CMS that rely on the login plugin for user authentication are at the highest risk. If an attacker obtains a legitimate user's password, they can leverage this flaw to effectively neutralize the second layer of security, leaving the account vulnerable to unauthorized access.

How the Flaw Works

This vulnerability falls into the category of authentication bypass flaws, which generally occur when an application fails to properly validate authorization tokens or user permissions during a multi-step verification process. In such scenarios, an attacker can typically manipulate the application's state—such as overwriting user-specific security configuration files—without the necessary administrative privileges. By bypassing standard CSRF protections or failing to verify session state during a TOTP challenge window, an attacker can force the system to accept illegitimate credentials or reset security parameters, effectively reducing a multi-factor authentication requirement to a single-factor password check.

How to Protect Your Systems

• Upgrade to Grav version 2.0.4 or later immediately to apply the vendor-supplied patch.
• Audit administrative logs for suspicious regenerate2FASecret activity or unexpected login patterns.
• Restrict access to administrative interfaces by implementing IP-based access control lists (ACLs).
• Ensure that all user accounts are protected by strong, unique passwords to prevent initial credential compromise.
• Follow vendor-recommended hardening guidelines for Grav CMS to minimize the attack surface of the login plugin.

Given the critical severity of this 7.4 CVSS-rated vulnerability, immediate action is required to secure affected environments. Failure to patch these systems leaves administrative accounts open to complete takeover if a password is compromised, highlighting the necessity of maintaining up-to-date software to defend against known authentication bypass mechanisms.