CVE-2026-92914 in AVideo
Summary
by MITRE • 09/17/2026
AVideo LoginControl contains an authentication bypass vulnerability in the PGP second factor verification that compares challenge responses using loose equality against an uninitialized session variable. Attackers with a victim's password can bypass the second factor by sending a parameter-less GET request to verifyChallenge.json.php, which evaluates null == null and marks authentication complete.
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Analysis
by VulDB Data Team • 09/17/2026
The vulnerability identified in AVideo LoginControl represents a critical failure in multi-factor authentication logic, specifically within the implementation of PGP-based two-step verification. This flaw stems from improper input validation and insecure comparison practices during the challenge-response phase of the authentication workflow. The core technical issue lies in how the application handles session state when verifying cryptographic signatures or encrypted responses against expected values. Instead of ensuring that a valid, non-null challenge token exists within the user's session before proceeding with verification, the system relies on loose equality operators to compare incoming parameters against uninitialized variables. In many programming languages and server-side environments, comparing null or undefined values using loose equality results in true if both sides are effectively empty or unset. This logical gap allows an attacker who has already obtained a victim's primary credentials, such as their username and password, to bypass the second factor entirely without possessing the private PGP key required for legitimate verification.
From a technical perspective, the exploitation vector involves sending a parameter-less GET request to the verifyChallenge.json.php endpoint. When this request is processed by the vulnerable code, it attempts to compare the missing or null challenge response from the client against an uninitialized session variable on the server side. Because both values are effectively null or empty at the point of comparison, the loose equality check evaluates as true. Consequently, the authentication module incorrectly interprets this match as a successful verification of the second factor. This behavior fundamentally undermines the security model of two-factor authentication, which is designed to require possession of something other than just knowledge (the password). By exploiting this logic error, an attacker can complete the login process with only the first factor, rendering the PGP integration ineffective for preventing unauthorized access in scenarios where primary credentials are compromised.
The operational impact of this vulnerability is severe, as it directly compromises the integrity of user accounts protected by what should be a robust secondary authentication layer. For organizations relying on AVideo to manage sensitive video content or user data, this flaw means that credential stuffing attacks, phishing campaigns, or simple password leaks can lead to full account takeover without any additional effort from the attacker beyond obtaining the initial login credentials. The absence of required parameters in the exploit request also makes detection more difficult for standard intrusion detection systems, as the traffic appears benign and does not trigger alerts associated with malformed requests or obvious injection attempts. This ease of exploitation significantly lowers the barrier to entry for attackers targeting users who have enabled PGP verification, assuming it provides a higher level of security than basic password-only access.
This vulnerability aligns closely with CWE-287 Improper Authentication, specifically regarding failures in verifying multi-factor authentication components. It also reflects aspects of CWE-613 Insufficient Session Expiration or CWE-940 Improper Verification of Complex Data Structures if the session state management is deemed flawed beyond just the comparison logic. In terms of offensive security frameworks, this attack pattern corresponds to MITRE ATT&CK technique T1078 Valid Accounts, where an adversary uses legitimate credentials but bypasses additional authentication controls through application-level flaws rather than credential theft or brute force. The specific method of exploiting a null equality check is also reminiscent of CWE-20 Improper Input Validation, as the system fails to enforce that required parameters are present and valid before processing sensitive security logic.
Mitigation strategies must focus on correcting the underlying code logic within the PGP verification module. Developers should replace loose equality comparisons with strict equality checks or explicit type checking functions that ensure both operands are defined and of the expected data type before proceeding. It is critical to validate that a challenge token has been generated, stored in the session, and matches the incoming response exactly; if no valid challenge exists in the session context for the current user, the verification process must fail immediately regardless of what parameters are sent by the client. Additionally, input validation should be implemented at the entry point of verifyChallenge.json.php to reject requests that do not contain all required fields, such as the encrypted signature or nonce value. Implementing these changes will ensure that authentication proceeds only when both factors are genuinely verified, restoring the intended security posture of the two-factor system.