CVE-2025-13262: Lsfusion Platform Path Traversal Flaw

CVE-2025-13262 Overview

A path traversal vulnerability has been identified in the lsfusion platform affecting versions up to 6.1. The vulnerability exists within the UploadFileRequestHandler function located in the file platform/web-client/src/main/java/lsfusion/http/controller/file/UploadFileRequestHandler.java. Attackers can exploit this vulnerability by manipulating the sid argument, enabling unauthorized access to files and directories outside the intended scope. This vulnerability can be exploited remotely without authentication, making it a significant security concern for organizations running affected versions.

Critical Impact

Remote attackers can exploit this path traversal vulnerability to read or potentially write files outside the intended directory, potentially accessing sensitive configuration files, credentials, or other critical system resources.

Affected Products

• lsfusion lsfusion_platform versions up to 6.1
• lsfusion Platform web-client component
• Applications built on lsfusion Platform with file upload functionality

Discovery Timeline

• 2025-11-17 - CVE CVE-2025-13262 published to NVD
• 2025-12-01 - Last updated in NVD database

Technical Details for CVE-2025-13262

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as path traversal or directory traversal. The flaw resides in the UploadFileRequestHandler class within the lsfusion Platform's web-client module.

The vulnerable component fails to properly sanitize the sid parameter before using it in file path operations. An attacker can craft malicious requests containing directory traversal sequences (such as ../) within the sid argument to escape the intended upload directory and access arbitrary files on the server's file system.

The vulnerability is accessible via network requests without requiring authentication, which significantly increases the risk of exploitation. The exploit has been publicly disclosed, meaning that threat actors may already have access to exploitation techniques.

Root Cause

The root cause of this vulnerability is inadequate input validation and sanitization of the sid parameter in the UploadFileRequestHandler.java file. The application fails to:

1. Properly validate that the sid parameter does not contain path traversal sequences
2. Canonicalize file paths before performing file operations
3. Verify that resolved paths remain within the expected directory boundaries

This allows attackers to inject relative path components that traverse outside the intended directory structure.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no prior authentication or user interaction. An attacker can exploit this vulnerability by:

1. Identifying an lsfusion Platform instance exposed to the network
2. Crafting HTTP requests to the file upload endpoint with a manipulated sid parameter
3. Including path traversal sequences (e.g., ../../../) in the sid value to navigate outside the intended directory
4. Accessing sensitive files such as configuration files, application source code, or system files

The vulnerability allows for reading potentially sensitive files and may enable writing files to arbitrary locations depending on the application's permissions and implementation details. For technical details and proof-of-concept information, refer to the GitHub Issue #1544 filed with the vendor.

Detection Methods for CVE-2025-13262

Indicators of Compromise

• HTTP requests to file upload endpoints containing path traversal sequences such as ../, ..\, or URL-encoded variants (%2e%2e%2f)
• Unusual file access patterns in web server logs targeting the UploadFileRequestHandler endpoint
• Attempts to access sensitive system files (e.g., /etc/passwd, configuration files) through web requests
• Unexpected file reads or writes outside the designated upload directories

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing path traversal patterns in the sid parameter
• Monitor HTTP request logs for suspicious patterns targeting the /file/upload or related endpoints
• Deploy intrusion detection system (IDS) signatures that identify directory traversal attempts in HTTP parameters
• Configure file integrity monitoring to detect unauthorized access to sensitive files

Monitoring Recommendations

• Enable detailed logging for the lsfusion Platform web-client module to capture all file operation requests
• Set up alerts for any requests containing encoded or decoded path traversal sequences
• Monitor file system access patterns for the lsfusion application user account to identify anomalous behavior
• Implement anomaly detection for file access outside expected application directories

How to Mitigate CVE-2025-13262

Immediate Actions Required

• Upgrade lsfusion Platform to a patched version that addresses CVE-2025-13262 when available
• Implement input validation at the web application firewall level to block path traversal attempts
• Restrict network access to the lsfusion Platform to trusted networks only where possible
• Review application logs for any signs of exploitation attempts

Patch Information

Organizations should monitor the lsfusion Platform GitHub repository for official patches and security updates addressing this vulnerability. The vendor has been notified through the GitHub issue tracking system. Apply patches as soon as they become available, following proper change management procedures.

Additional vulnerability details are available through VulDB.

Workarounds

• Deploy a web application firewall (WAF) rule to filter requests containing path traversal patterns (../, ..\, %2e%2e) in the sid parameter
• Implement network segmentation to limit access to the lsfusion Platform from untrusted networks
• Configure server-side file system permissions to restrict the application's access to only necessary directories
• Consider disabling the file upload functionality temporarily if it is not business-critical until a patch is available

# Example WAF rule for ModSecurity to block path traversal attempts
SecRule ARGS:sid "@rx (\.\./|\.\.\\|%2e%2e)" \
    "id:100001,\
    phase:2,\
    deny,\
    status:403,\
    log,\
    msg:'Path Traversal Attempt Detected in sid Parameter - CVE-2025-13262'"