CVE-2026-2672: Tsinghua Unigroup Path Traversal Flaw

CVE-2026-2672 Overview

A path traversal vulnerability has been discovered in Tsinghua Unigroup Electronic Archives System version 3.2.210802(62532). This security flaw affects the Download function located in the file /Search/Subject/downLoad. By manipulating the path argument, an attacker can traverse directories and potentially access arbitrary files on the affected system. The vulnerability can be exploited remotely by authenticated users, and a public exploit has been released, increasing the risk of active exploitation.

Critical Impact

Authenticated attackers can exploit this path traversal vulnerability to read sensitive files outside the intended directory, potentially exposing configuration files, credentials, and other confidential system data.

Affected Products

• Tsinghua Unigroup Electronic Archives System 3.2.210802(62532)

Discovery Timeline

• 2026-02-18 - CVE CVE-2026-2672 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-2672

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 file download functionality of the Electronic Archives System, specifically within the Download function that handles file retrieval requests.

The core issue stems from insufficient validation of user-supplied input in the path parameter. When a user requests a file download through the /Search/Subject/downLoad endpoint, the application fails to properly sanitize the path value before using it to locate and serve the requested file. This allows attackers to use directory traversal sequences (such as ../) to escape the intended directory structure and access files elsewhere on the file system.

The vulnerability enables remote exploitation over the network, though authentication is required. Given that a proof-of-concept exploit has been publicly released, organizations using this system face elevated risk as attackers can readily weaponize this vulnerability.

Root Cause

The root cause of this vulnerability is improper input validation in the Download function. The application accepts user-controlled input for the path parameter without adequately sanitizing or validating the value to ensure it remains within the intended file directory. The absence of path canonicalization and boundary checking allows malicious traversal sequences to be processed, enabling access to files outside the document root.

Attack Vector

The attack vector is network-based and requires low-privilege authentication to the Electronic Archives System. An attacker with valid credentials can craft a malicious HTTP request to the /Search/Subject/downLoad endpoint with a manipulated path parameter containing directory traversal sequences.

The attack flow involves submitting a request where the path argument includes sequences like ../ to navigate up the directory tree. For example, an attacker could attempt to read sensitive system files such as configuration files or credential stores by traversing to known file locations. The vulnerability requires no user interaction and can be exploited with relatively low technical complexity.

For technical details regarding the exploitation mechanism, see the GitHub PoC Repository and proof of concept script.

Detection Methods for CVE-2026-2672

Indicators of Compromise

• HTTP requests to /Search/Subject/downLoad containing path traversal sequences such as ../, ..%2f, %2e%2e/, or %2e%2e%5c
• Unusual file access patterns in web server logs showing attempts to access files outside the archives directory
• Access attempts to sensitive system files like /etc/passwd, configuration files, or database credentials through the download endpoint
• High volume of download requests from a single source attempting various path combinations

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing path traversal patterns in URL parameters
• Configure intrusion detection systems (IDS) to alert on HTTP requests with encoded or plain-text directory traversal sequences targeting the affected endpoint
• Monitor web application logs for anomalous download requests, particularly those with suspicious path values or repeated access failures

Monitoring Recommendations

• Enable detailed logging for the /Search/Subject/downLoad endpoint and regularly review logs for suspicious activity
• Set up real-time alerting for any access attempts to sensitive system directories through the vulnerable function
• Implement file integrity monitoring on critical system files to detect unauthorized access or modifications

How to Mitigate CVE-2026-2672

Immediate Actions Required

• Restrict network access to the Tsinghua Unigroup Electronic Archives System to trusted IP addresses only until a patch is available
• Implement input validation at the web application firewall level to block path traversal sequences
• Review and restrict the file system permissions of the web application service account to minimize the impact of potential exploitation
• Audit system access logs to identify any potential exploitation attempts that may have already occurred

Patch Information

As of the last update on 2026-02-19, the vendor (Tsinghua Unigroup) has not responded to disclosure attempts and no official patch is available. Organizations should implement compensating controls and monitor for vendor security advisories. For additional context, consult the VulDB entry for this vulnerability.

Workarounds

• Deploy a web application firewall with rules configured to reject requests containing path traversal patterns (../, encoded variants, and null bytes) in the path parameter
• Implement a reverse proxy that validates and sanitizes the path parameter before forwarding requests to the application
• If feasible, disable the file download functionality at /Search/Subject/downLoad until official remediation is available
• Restrict user permissions within the application to limit the number of accounts capable of accessing the download functionality

# Example WAF rule for blocking path traversal attempts (ModSecurity)
SecRule ARGS:path "@rx (\.\./|\.\.\\|%2e%2e%2f|%2e%2e/|%252e%252e%252f)" \
    "id:100001,phase:2,deny,status:403,msg:'Path traversal attempt blocked',log,auditlog"