CVE-2026-4542: SSCMS Path Traversal Vulnerability

CVE-2026-4542 Overview

A path traversal vulnerability has been identified in SSCMS version 4.7.0, affecting the LayerImageController.Submit.cs file within the layerImage endpoint component. This vulnerability allows remote attackers to manipulate the filePaths argument to traverse directories and potentially access or modify files outside the intended directory structure. The exploit has been publicly disclosed and may be actively used in the wild.

Critical Impact

Remote attackers can exploit this path traversal vulnerability to access sensitive files, potentially leading to information disclosure or system compromise through unauthorized file operations.

Affected Products

• SSCMS 4.7.0

Discovery Timeline

• 2026-03-22 - CVE-2026-4542 published to NVD
• 2026-03-23 - Last updated in NVD database

Technical Details for CVE-2026-4542

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 exists in the LayerImageController.Submit.cs file, which handles file path processing for the layerImage endpoint. When processing user-supplied input through the filePaths argument, the application fails to properly sanitize or validate the path components, allowing attackers to use directory traversal sequences (such as ../) to escape the intended directory context.

The network-accessible nature of the layerImage endpoint means that any authenticated user with low-level privileges can potentially exploit this vulnerability. The impact includes unauthorized read or write access to files on the system, which could lead to information disclosure of sensitive configuration files, application source code, or user data.

Root Cause

The root cause of this vulnerability lies in insufficient input validation within the LayerImageController.Submit.cs file. The application does not properly sanitize the filePaths parameter before using it in file system operations. This allows malicious path traversal sequences to be processed, enabling attackers to reference files and directories outside the intended scope of the application's file handling logic.

Attack Vector

The attack can be performed remotely over the network by an authenticated attacker with low-level privileges. The attacker crafts a malicious request to the layerImage endpoint, including directory traversal sequences in the filePaths parameter. These sequences allow the attacker to navigate outside the designated file directory and access arbitrary files on the server.

The vulnerability does not require user interaction beyond the attacker's own authentication, making it straightforward to exploit once an attacker has basic access to the application. According to the vulnerability disclosure, this exploit methodology has been made public, increasing the risk of widespread exploitation attempts.

Detection Methods for CVE-2026-4542

Indicators of Compromise

• HTTP requests to the layerImage endpoint containing directory traversal sequences such as ../ or ..\ in the filePaths parameter
• Unusual file access patterns in server logs showing access to system files or directories outside the web application root
• Error messages or log entries indicating failed file operations in unexpected directories
• Anomalous authenticated user activity targeting image upload or management functionality

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block path traversal patterns in request parameters
• Configure intrusion detection systems (IDS) to alert on HTTP requests containing directory traversal sequences targeting SSCMS endpoints
• Deploy application-level logging to monitor all file path operations within the layerImage controller
• Review authentication logs for accounts exhibiting suspicious behavior patterns targeting file management endpoints

Monitoring Recommendations

• Enable detailed logging for the layerImage endpoint and all file system operations within SSCMS
• Configure real-time alerting for any detected path traversal attempts in web server and application logs
• Implement file integrity monitoring (FIM) on critical system and configuration files to detect unauthorized access or modifications
• Monitor network traffic for patterns consistent with automated exploitation attempts targeting SSCMS installations

How to Mitigate CVE-2026-4542

Immediate Actions Required

• Review and restrict access to the layerImage endpoint to only essential users while awaiting a patch
• Implement input validation rules at the web server or WAF level to block path traversal sequences
• Audit user accounts with access to the affected functionality and revoke unnecessary privileges
• Monitor server logs for any signs of exploitation attempts or unauthorized file access

Patch Information

No official vendor patch information is currently available in the CVE data. Organizations running SSCMS 4.7.0 should monitor the official SSCMS project and VulDB #352359 for updates regarding security patches. Additional technical details may be found in the Yuque Documentation Article.

Workarounds

• Deploy a web application firewall (WAF) with rules to filter and block path traversal patterns in all request parameters
• Implement server-side input validation to reject any file path containing ../, ..\, or other traversal sequences
• Restrict file system permissions for the web application user to limit access to only required directories
• Consider temporarily disabling or restricting access to the layerImage functionality until a patch is available

# Example WAF rule configuration (ModSecurity)
SecRule ARGS "@rx \.\./|\.\.\\|%2e%2e" "id:100001,phase:2,deny,status:403,msg:'Path Traversal Attempt Detected in SSCMS'"