CVE-2025-53826 in filebrowser
Summary
by MITRE • 07/15/2025
File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, preview, rename, and edit files. In version 2.39.0, File Browser’s authentication system issues long-lived JWT tokens that remain valid even after the user logs out. As of time of publication, no known patches exist.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/05/2025
The vulnerability identified as CVE-2025-53826 represents a critical authentication flaw in File Browser version 2.39.0 that fundamentally compromises the security of the system. This issue stems from the application's improper handling of session management where JWT tokens are issued with extended lifespans that persist beyond the logical termination of user sessions. The flaw directly violates established security principles for session management and access control, creating a persistent vector for unauthorized access that remains active even after legitimate users have attempted to end their sessions through standard logout procedures. The vulnerability is particularly concerning because it affects the core authentication mechanism of the application, which is designed to provide file management capabilities within specified directories while maintaining secure access controls.
The technical implementation of this vulnerability involves the generation and issuance of JSON Web Tokens that lack proper session invalidation mechanisms. When users authenticate to File Browser, the system creates a JWT token that contains authentication claims and a long expiration time, typically measured in days or weeks rather than hours or minutes. This design choice, while potentially intended to improve user experience by reducing the frequency of re-authentication, creates a dangerous security artifact where tokens remain valid indefinitely unless manually revoked or expired. The flaw is classified as a weakness in authentication mechanisms under CWE-305 and represents a failure in session management practices that aligns with ATT&CK technique T1566 for credential access through session hijacking. The long-lived nature of these tokens means that any compromise of the token itself, whether through network interception, client-side vulnerabilities, or insider threats, provides persistent access to the file management system.
The operational impact of this vulnerability extends far beyond simple unauthorized access to file management capabilities. Attackers who obtain valid JWT tokens can maintain persistent access to the system indefinitely, potentially enabling data exfiltration, file manipulation, and privilege escalation within the scope of the compromised account. The vulnerability affects all users of the affected version regardless of their privilege level, making it particularly dangerous in environments where the file browser serves as a gateway to sensitive data repositories or system management interfaces. Organizations using File Browser in production environments face significant risk of unauthorized data access, potential compliance violations, and operational disruption. The lack of available patches at the time of publication compounds the risk, leaving administrators with no immediate remediation options and forcing them to implement workarounds or alternative security measures to protect their systems.
Mitigation strategies for this vulnerability require immediate implementation of compensating controls given the absence of official patches. Organizations should implement additional authentication layers such as multi-factor authentication to reduce the impact of token compromise, establish strict network access controls to limit exposure, and deploy monitoring solutions to detect unusual token usage patterns. The implementation of token revocation mechanisms, even if not native to the application, should be considered through proxy solutions or API gateways that can invalidate tokens when users log out. Network segmentation and least privilege access principles should be enforced to limit the scope of potential damage from compromised tokens. Security teams should also consider implementing automated token lifecycle management, regular token rotation policies, and comprehensive monitoring of authentication events to detect potential exploitation attempts. The vulnerability highlights the critical importance of proper session management in web applications and serves as a reminder of the necessity for robust access control mechanisms that properly handle session termination and token invalidation processes.