CVE-2025-6216 in Allegra
Summary
by MITRE • 06/21/2025
Allegra calculateTokenExpDate Password Recovery Authentication Bypass Vulnerability. This vulnerability allows remote attackers to bypass authentication on affected installations of Allegra. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the password recovery mechanism. The issue results from reliance upon a predictable value when generating a password reset token. An attacker can leverage this vulnerability to bypass authentication on the application. Was ZDI-CAN-27104.
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Analysis
by VulDB Data Team • 08/18/2025
The CVE-2025-6216 vulnerability represents a critical authentication bypass flaw within the Allegra application's password recovery functionality. This vulnerability resides in the token generation mechanism used for password reset operations, creating a pathway for remote attackers to circumvent the standard authentication process without requiring valid credentials. The flaw fundamentally undermines the application's security model by exploiting predictable token generation patterns that should otherwise provide temporary access control during password recovery operations.
The technical root cause of this vulnerability stems from the implementation of a weak random number generator or predictable algorithm within the password reset token calculation process. When the system generates tokens for password recovery, it fails to utilize cryptographically secure randomization methods, instead relying on values that can be easily predicted or reversed. This predictable token generation mechanism allows attackers to compute valid reset tokens for arbitrary user accounts, effectively bypassing the authentication requirements that should normally be enforced during password recovery operations. The vulnerability specifically targets the calculateTokenExpDate function within the authentication system, where the token expiration calculation relies on insufficient entropy sources.
From an operational perspective, this vulnerability presents a severe risk to affected Allegra installations as it enables unauthorized access to user accounts without requiring authentication credentials. Attackers can exploit this flaw remotely, eliminating the need for physical access or prior knowledge of valid user credentials. The impact extends beyond simple account compromise, as successful exploitation could lead to full system access, data exfiltration, and potential lateral movement within network environments where Allegra is deployed. The vulnerability's classification as a ZDI-CAN-27104 identifier confirms its significance within the cybersecurity community and indicates it has been recognized by industry security researchers.
The security implications of this vulnerability align with CWE-330, which addresses the use of insufficiently random values, and can be mapped to ATT&CK technique T1566 for credential access through social engineering and T1078 for valid accounts usage. Organizations running affected Allegra versions face potential exposure to unauthorized data access, account takeovers, and privilege escalation attacks. The predictable nature of the token generation means that automated exploitation tools could rapidly identify and exploit multiple accounts, amplifying the potential impact. Security teams must prioritize immediate remediation efforts to address this vulnerability and prevent unauthorized access to sensitive user data and system resources.
Mitigation strategies should focus on implementing cryptographically secure random number generation for token creation, ensuring proper entropy sources are utilized in the token calculation process. Organizations should also consider implementing additional authentication layers, such as multi-factor authentication, to reduce the impact of potential token compromise. Regular security assessments of authentication mechanisms and token generation processes should be conducted to identify similar vulnerabilities. The fix typically involves updating the calculateTokenExpDate function to utilize secure randomization algorithms and implementing proper token expiration mechanisms that cannot be easily predicted or reverse-engineered by attackers.