CVE-2025-62166 in FreshRSS
Summary
by MITRE • 03/09/2026
FreshRSS is a free, self-hostable RSS aggregator. Prior 1.28.0, a bug in the auth logic related to master authentication tokens, this restriction is bypassed. Usually only the default user's feed should be viewable if anonymous viewing is enabled, and feeds of other users should be private. This vulnerability is fixed in 1.28.0.
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Analysis
by VulDB Data Team • 03/12/2026
FreshRSS represents a widely-used self-hostable rss aggregator that enables users to collect and manage news feeds from various sources. The vulnerability identified as CVE-2025-62166 specifically targets the application's authentication mechanism, particularly concerning master authentication tokens that govern access controls within the system. This flaw exists in versions prior to 1.28.0 and fundamentally undermines the application's security model by allowing unauthorized access to user-specific content. The vulnerability stems from a failure in the authentication logic where the system does not properly enforce access restrictions based on user permissions. When anonymous viewing is enabled, the system should typically restrict feed visibility to only the default user's content while maintaining privacy for feeds belonging to other users. However, this security boundary is compromised due to the flawed token handling mechanism.
The technical implementation of this vulnerability involves the improper validation of authentication tokens during access requests. Master authentication tokens are designed to provide elevated privileges for administrative functions while maintaining proper segregation between different user accounts. When these tokens are processed incorrectly, they fail to verify whether the requesting user has legitimate authorization to access specific feed content. This flaw creates a privilege escalation scenario where any authenticated user can potentially access feeds belonging to other users within the same FreshRSS instance. The vulnerability directly relates to CWE-285 which addresses improper authorization in authentication mechanisms and aligns with ATT&CK technique T1078 which covers valid accounts for lateral movement and privilege escalation.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential data breaches and unauthorized access to private user content. Attackers exploiting this vulnerability could gain access to feeds that should remain private to specific users, potentially exposing sensitive information or personal reading preferences. This compromise affects the fundamental privacy guarantees that users expect from a self-hosted rss aggregator. The vulnerability particularly impacts organizations or individuals who rely on FreshRSS for managing multiple user accounts where feed content might contain confidential or proprietary information. The breach of access controls undermines the trust model that users place in self-hosted applications and could lead to reputational damage for administrators who fail to maintain proper security configurations. Organizations using FreshRSS without implementing proper security updates face significant risk of unauthorized data access and potential compliance violations.
Mitigation strategies for this vulnerability require immediate implementation of the security patch available in FreshRSS version 1.28.0. System administrators should conduct comprehensive security audits to ensure all instances are updated to the latest stable release. Additional protective measures include implementing network segmentation to limit access to FreshRSS installations, enabling strong authentication mechanisms, and monitoring access logs for suspicious activities. Organizations should also consider implementing additional access controls beyond the default configuration, such as disabling anonymous viewing when not required, and regularly reviewing user permissions. The vulnerability highlights the importance of maintaining up-to-date security practices and demonstrates the critical nature of proper authentication token validation in web applications. Security teams should implement automated patch management processes to prevent similar issues from arising in the future. Regular security assessments and penetration testing can help identify potential authorization flaws before they can be exploited by malicious actors.