CVE-2025-53893 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 2.38.0, a Denial of Service (DoS) vulnerability exists in the file processing logic when reading a file on endpoint `Filebrowser-Server-IP:PORT/files/{file-name}` . While the server correctly handles and stores uploaded files, it attempts to load the entire content into memory during read operations without size checks or resource limits. This allows an authenticated user to upload a large file and trigger uncontrolled memory consumption on read, potentially crashing the server and making it unresponsive. As of time of publication, no known patches are available.
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Analysis
by VulDB Data Team • 08/05/2025
The vulnerability described in CVE-2025-53893 represents a critical denial of service weakness within the File Browser application version 2.38.0. This issue stems from inadequate resource management during file read operations, specifically affecting the endpoint at Filebrowser-Server-IP:PORT/files/{file-name}. The flaw occurs when the server attempts to load entire file contents into memory without implementing size validation or resource consumption limits, creating a scenario where malicious or unauthorized users can exploit this weakness to disrupt service availability. The vulnerability is particularly concerning because it requires only authenticated access to exploit, meaning that any user with valid credentials can potentially trigger the denial of service condition.
The technical implementation of this vulnerability resides in the server's file reading logic where it processes file content without proper memory allocation controls or size verification mechanisms. When an authenticated user uploads a large file and subsequently attempts to read it through the designated endpoint, the system attempts to load the complete file content into memory. This approach violates fundamental security principles for resource management and can lead to uncontrolled memory consumption. The absence of any size limits or memory allocation checks means that the server's memory resources can be exhausted rapidly, leading to system instability and eventual service disruption. This behavior aligns with CWE-400, which categorizes uncontrolled resource consumption as a significant security weakness that can lead to denial of service conditions.
From an operational impact perspective, this vulnerability creates a substantial risk to system availability and service integrity. The server becomes vulnerable to memory exhaustion attacks that can render it completely unresponsive, effectively denying legitimate users access to the file management functionality. The DoS condition can persist until the server is manually restarted or the memory is cleared, creating potential downtime that could impact business operations and user productivity. The vulnerability's exploitation requires minimal technical skill and only authenticated access, making it particularly dangerous in environments where user access controls may be insufficient or where users with legitimate access could be compromised. This weakness can be leveraged by both malicious insiders and external attackers who have gained valid credentials to the system.
Organizations affected by this vulnerability should implement immediate mitigations while awaiting potential patches or updates from the vendor. The most effective immediate solution involves implementing strict file size limits and memory consumption controls within the server configuration to prevent the loading of excessively large files into memory. Additionally, monitoring systems should be enhanced to detect unusual memory consumption patterns that could indicate exploitation attempts. Network-level controls and rate limiting can also help mitigate the impact by restricting the number of file read operations that can be performed within a given time period. Security teams should also consider implementing automated alerts when memory usage exceeds normal thresholds, providing early detection capabilities for potential exploitation attempts. The vulnerability demonstrates the importance of applying the principle of least privilege and implementing proper resource management controls as outlined in the mitre ATT&CK framework's resource exhaustion techniques, which emphasize the need for defensive measures against memory consumption attacks. Organizations should also review their access control policies to ensure that only authorized users have the necessary permissions to perform file read operations that could trigger this vulnerability.