CVE-2026-73431 in Vulnerability-Lookup
Summary
by MITRE • 08/12/2026
Vulnerability-Lookup contains an authentication weakness in its account activation and password-recovery mechanism. Activation and recovery links were generated using stateless signed tokens containing only the user's login. Although the token signature and age were validated, the application did not track whether a token had already been successfully used. As a result, a captured activation or password-recovery link remained valid for the entire configured TOKEN_VALIDITY_PERIOD, even after the associated password had been changed.
An attacker who obtains a valid activation or recovery token could therefore replay it multiple times during its validity period to set a new password and repeatedly take control of the affected account. In addition, tokens were not bound to a specific purpose, allowing the same token mechanism to be used across activation and recovery workflows. The patch introduces purpose-bound tokens and a random nonce whose SHA-256 digest is stored with the user account. The nonce is invalidated after a successful password change, making tokens single-use, while issuing a new token invalidates any previously issued token. The password-setting operation now explicitly consumes the token before committing the account change.
Successful exploitation requires the attacker to obtain a currently valid activation or recovery link, but does not require knowledge of the victim's existing password or an authenticated session.
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Analysis
by VulDB Data Team • 08/12/2026
This vulnerability represents a critical authentication weakness that undermines the security of user account management processes within the application. The flaw resides in the account activation and password recovery mechanisms where stateless signed tokens are generated containing only the user's login identifier without any tracking mechanism for token usage. According to the common weakness enumeration standard CWE-384, this constitutes a session management vulnerability where tokens lack proper state tracking, creating a window of opportunity for attackers to exploit the system. The tokens were designed with signature validation and age checking but failed to implement token consumption tracking, allowing replay attacks to succeed within the configured TOKEN_VALIDITY_PERIOD regardless of whether the associated password had been changed.
The operational impact of this vulnerability extends beyond simple account compromise as it enables persistent unauthorized access through repeated token reuse during their validity period. An attacker who intercepts a valid activation or recovery link can repeatedly execute the token to reset passwords and gain control of user accounts multiple times, effectively bypassing normal security controls that should prevent such abuse. This weakness aligns with ATT&CK technique T1566 which describes credential access through social engineering and compromised credentials, but in this case the compromise occurs through token interception rather than traditional password guessing or cracking methods. The lack of purpose binding for tokens creates additional risk as identical mechanisms are used across different security workflows, amplifying the potential attack surface.
The mitigation strategy implemented addresses these issues by introducing purpose-bound tokens that are specifically designed for either activation or recovery functions, eliminating cross-purpose token usage that previously enabled exploitation. A random nonce is now generated and stored as a SHA-256 digest associated with each user account, providing a mechanism to track token consumption. This approach ensures that tokens become single-use after successful password changes, with the nonce being invalidated upon successful completion of the password reset process. The patch enforces explicit token consumption during the password-setting operation before any account modifications are committed, following secure coding practices recommended by OWASP and NIST guidelines for authentication system design. Additionally, issuing new tokens now automatically invalidates previously issued tokens for the same user, creating a proper state management mechanism that prevents replay attacks while maintaining legitimate user functionality.
The attack requirements for successful exploitation remain minimal as attackers only need to obtain a currently valid token through interception or other means, without requiring knowledge of existing passwords or authenticated sessions. This makes the vulnerability particularly dangerous as it can be exploited by attackers with limited access to the system, potentially leading to account takeover and unauthorized access to sensitive user data. The fix ensures that each token can only be consumed once, effectively closing the door to repeated exploitation while maintaining legitimate account recovery functionality for authorized users who obtain valid tokens through proper channels.