CVE-2026-25059: OpenList Frontend Path Traversal Flaw

CVE-2026-25059 Overview

CVE-2026-25059 is a path traversal vulnerability affecting OpenList Frontend, a UI component for OpenList. Prior to version 4.1.10, the application contains a path traversal vulnerability in multiple file operation handlers within server/handles/fsmanage.go. Filename components in req.Names are directly concatenated with validated directories using stdpath.Join, allowing .. sequences to bypass path restrictions. This enables authenticated users to access other users' files within the same storage mount and perform unauthorized actions such as deletion, renaming, or copying of files.

Critical Impact

An authenticated attacker can bypass directory-level authorization by injecting traversal sequences into filename components, enabling unauthorized file removal and copying across user boundaries within the same storage mount.

Affected Products

• OpenList Frontend versions prior to 4.1.10
• OpenList deployments using shared storage mounts
• Systems with multi-user file management configurations

Discovery Timeline

• 2026-02-02 - CVE-2026-25059 published to NVD
• 2026-02-03 - Last updated in NVD database

Technical Details for CVE-2026-25059

Vulnerability Analysis

This path traversal vulnerability (CWE-22) exists in the file operation handlers of OpenList Frontend. The root issue lies in how the application processes user-supplied filename parameters when performing file system operations. When a user submits file operation requests, the req.Names array containing filenames is directly passed to stdpath.Join() without adequate sanitization of path traversal sequences.

The stdpath.Join() function in Go does normalize paths and resolve .. sequences, but when the base directory validation occurs before the join operation, an attacker can still escape the intended directory boundary. This allows authenticated users to manipulate files belonging to other users who share the same storage mount point, effectively breaking the multi-tenant isolation model.

Root Cause

The vulnerability stems from insufficient input validation in the file management handlers located in server/handles/fsmanage.go. The application validates the target directory path but fails to properly sanitize individual filename components before concatenation. When filenames containing .. sequences are joined with the validated directory path, the resulting path can resolve to locations outside the user's authorized directory, enabling unauthorized cross-user file access within shared storage mounts.

Attack Vector

The attack is network-based and requires authentication. An attacker with valid credentials can craft malicious requests containing directory traversal sequences in the filename parameters. By injecting .. patterns into the Names field of file operation requests (such as delete, rename, or copy operations), the attacker can target files belonging to other users on the same storage mount. The low complexity of this attack vector combined with the lack of required user interaction makes exploitation straightforward for any authenticated malicious actor.

// Security patch in server/handles/archive.go
// Source: https://github.com/OpenListTeam/OpenList/commit/7b78fed106382430c69ef351d43f5d09928fff14

 type ArchiveDecompressReq struct {
 	SrcDir        string   `json:"src_dir" form:"src_dir"`
 	DstDir        string   `json:"dst_dir" form:"dst_dir"`
-	Name          []string `json:"name" form:"name"`
+	Names         []string `json:"name" form:"name"`
 	ArchivePass   string   `json:"archive_pass" form:"archive_pass"`
 	InnerPath     string   `json:"inner_path" form:"inner_path"`
 	CacheFull     bool     `json:"cache_full" form:"cache_full"`

The patch shown above is part of the broader security fix addressing the path traversal vulnerability. See the GitHub Security Advisory for complete technical details.

Detection Methods for CVE-2026-25059

Indicators of Compromise

• HTTP requests to file operation endpoints containing .. sequences in filename parameters
• Unusual file access patterns where users access or modify files outside their designated directories
• Log entries showing file operations with path components that include parent directory references
• Cross-user file deletions, renames, or copies that bypass expected directory boundaries

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing .. or encoded variants (%2e%2e) in file operation parameters
• Monitor application logs for file operations targeting paths outside user-specific directories
• Deploy runtime application self-protection (RASP) solutions to detect path traversal attempts at the application layer
• Create alerts for file system operations that reference parent directories within the storage mount

Monitoring Recommendations

• Enable detailed logging for all file operation endpoints in OpenList, particularly fsmanage.go handlers
• Configure centralized log collection to correlate file access patterns across users sharing storage mounts
• Establish baseline file access patterns per user to identify anomalous cross-boundary access attempts
• Monitor for elevated rates of file operation errors that may indicate exploitation attempts

How to Mitigate CVE-2026-25059

Immediate Actions Required

• Upgrade OpenList Frontend to version 4.1.10 or later immediately
• Audit file system logs for evidence of unauthorized cross-user file access prior to patching
• Review user activity logs for suspicious file operations containing traversal patterns
• Consider temporarily restricting file operation capabilities until the patch is applied

Patch Information

The vulnerability has been fixed in OpenList Frontend version 4.1.10. The security patch is available through the official GitHub Release v4.1.10. The fix addresses the path traversal issue by implementing proper input validation and path sanitization for filename components before processing file operations. Organizations should review the commit details to understand the specific changes made.

Workarounds

• Implement reverse proxy rules to filter requests containing .. sequences in file operation parameters
• Restrict file operation permissions at the storage mount level to limit potential cross-user access
• Deploy network-level access controls to limit which users can reach file management endpoints
• Consider isolating user storage into separate mount points to reduce the impact of potential exploitation

# Example nginx configuration to block path traversal attempts
location /api/fs/ {
    # Block requests containing path traversal sequences
    if ($request_uri ~* "\.\.") {
        return 403;
    }
    proxy_pass http://openlist_backend;
}