CVE-2025-27553 - Relative Path Traversal Vulnerability in Apache Commons VFS Before 2.10.

A relative path traversal vulnerability (CVE-2025-27553) has been discovered in Apache Commons VFS (Virtual File System) library versions before 2.10.. This vulnerability allows an attacker to bypass the "resolveFile" method's "NameScope" functionality and potentially access sensitive files and data on the affected system. This post will provide an overview of the vulnerability, its impact, and mitigation steps.

Vulnerability Details

Apache Commons VFS is a popular library used for implementing a virtual file system in Java applications. It provides various FileObject APIs that help developers work with numerous file systems, such as local, remote, and in-memory file systems.

One such API is the 'resolveFile' method, which takes a 'scope' parameter. Using the 'NameScope.DESCENDENT' value promises that "an exception is thrown if the resolved file is not a descendent of the base file." However, when the path contains encoded ".." characters (for example, "%2E%2E/bar.txt"), the 'resolveFile' method might return file objects that are not a descendent of the base file, without throwing an exception.

Here is a code snippet illustrating the issue

FileSystemManager fsManager = VFS.getManager();
FileObject baseFile = fsManager.resolveFile("/path/to/base");
FileObject resolvedFile = baseFile.resolveFile("%2E%2E/bar.txt", NameScope.DESCENDENT);

// The resolvedFile should not be accessible as it is not a descendent of the base file, but it still resolves

The vulnerability can be exploited by a malicious user to access files and folders outside the intended scope, potentially leading to unauthorized access to sensitive data or even remote code execution.

Affected Versions

This issue affects Apache Commons VFS versions prior to 2.10..

Mitigation Steps

To mitigate this vulnerability, users are advised to upgrade their Apache Commons VFS library to version 2.10., which resolves the issue. The latest version can be downloaded from the official Apache Commons VFS website.

For more details on this vulnerability, refer to the following

- CVE-2025-27553 - NVD Detail
- Apache Commons VFS Vulnerability Report
- Apache Commons VFS Official Website

Timeline

Published on: 03/23/2025 15:15:13 UTC
Last modified on: 04/02/2025 22:15:19 UTC