CVE-2026-62232 in Grav
Summary
by MITRE • 07/17/2026
Grav before 2.0.4 contains a two-factor authentication bypass vulnerability in the login plugin where the regenerate2FASecret task checks only user existence, not authorization, during the pending TOTP challenge window. Attackers who know the victim's password can call this task without a CSRF nonce to overwrite the 2FA secret with an attacker-chosen value, compute a valid TOTP code, and complete authentication while reducing 2FA to password-only protection.
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Analysis
by VulDB Data Team • 07/17/2026
The vulnerability in Grav before version 2.0.4 represents a critical security flaw that undermines the integrity of two-factor authentication mechanisms within the login plugin. This issue stems from a fundamental design weakness in the regenerate2FASecret task implementation, where the system fails to properly validate user authorization before executing sensitive operations. The flaw exists specifically during the pending TOTP challenge window, creating a temporal vulnerability window that attackers can exploit.
The technical execution of this bypass requires an attacker to possess the victim's password, which then allows them to call the regenerate2FASecret task without proper CSRF protection mechanisms. This omission in the security validation process means that the system only verifies user existence rather than confirming proper authorization rights. The absence of CSRF nonce verification creates a direct pathway for unauthorized modification of 2FA secrets, effectively allowing attackers to overwrite legitimate TOTP configurations with attacker-controlled values.
The operational impact of this vulnerability extends beyond simple credential theft, as it completely neutralizes the two-factor authentication protection that users rely upon for enhanced security. When an attacker successfully overwrites the TOTP secret, they can compute a valid time-based one-time password code that aligns with their chosen secret value. This manipulation results in a complete bypass of the 2FA mechanism, reducing multi-factor protection down to single-factor password authentication. The vulnerability essentially transforms robust two-factor security into a vulnerable single-factor system, providing attackers with elevated privileges and persistent access.
This vulnerability maps directly to CWE-306, which addresses "Missing Authentication for Critical Function," and aligns with ATT&CK technique T1078.004 for Valid Accounts and T1566.002 for Phishing. The flaw demonstrates poor input validation and insufficient authorization checks during critical authentication operations. Security practitioners should immediately implement mitigations including immediate patching to version 2.0.4 or later, implementing proper CSRF protection mechanisms, and ensuring that all sensitive administrative tasks require proper authorization verification before execution.
The root cause of this issue lies in inadequate security controls during the pending TOTP challenge window, where the system assumes that user existence validation is sufficient for authorization purposes. This design oversight creates a dangerous assumption that user authentication status alone provides adequate protection for sensitive operations. Organizations using Grav should conduct comprehensive security audits to identify similar authorization gaps in their authentication mechanisms and implement proper session management controls that verify both user identity and authorization rights before executing administrative functions.
The vulnerability serves as a stark reminder of the importance of proper authorization verification in all critical system functions, particularly those involving authentication and security configuration changes. Modern security frameworks emphasize that authorization checks must be performed at every level of system interaction, especially during transitional states such as pending challenge windows where users are in a vulnerable authentication state. The absence of these controls creates exploitable conditions that can lead to complete system compromise when combined with knowledge of valid user credentials.
Organizations should implement layered defensive strategies including network segmentation, monitoring for unusual administrative activity patterns, and regular security assessments of authentication mechanisms. The fix requires not only updating the software but also establishing proper security protocols that ensure all sensitive operations require multiple validation factors before execution. This vulnerability highlights the need for comprehensive security testing that includes authorization verification scenarios to prevent similar issues in other systems.
The security implications extend beyond immediate exploitation potential, as this flaw demonstrates how seemingly minor implementation oversights can create significant security risks. The vulnerability represents a failure in defense-in-depth principles where multiple layers of security should protect critical functions but instead created a single point of failure. This type of vulnerability is particularly concerning for web applications that handle sensitive user data and require robust authentication mechanisms to maintain system integrity and user trust.