CVE-2026-4285: easegen-admin Path Traversal Vulnerability

CVE-2026-4285 Overview

A path traversal vulnerability has been identified in taoofagi easegen-admin affecting the recognizeMarkdown function within the Pdf2MdUtil.java file. The vulnerability exists in the yudao-module-digitalcourse component and can be exploited remotely by manipulating the fileUrl argument to traverse directories outside the intended scope. The exploit has been publicly disclosed, and the vendor has not responded to security disclosure attempts.

Critical Impact

Remote attackers with high privileges can exploit this path traversal vulnerability to access files outside the intended directory structure, potentially leading to unauthorized information disclosure.

Affected Products

• taoofagi easegen-admin (up to commit 8f87936ac774065b92fb20aab55b274a6ea76433)
• yudao-module-digitalcourse-biz component
• Pdf2MdUtil.java utility class

Discovery Timeline

• 2026-03-17 - CVE-2026-4285 published to NVD
• 2026-03-17 - Last updated in NVD database

Technical Details for CVE-2026-4285

Vulnerability Analysis

This path traversal vulnerability (CWE-22) affects the recognizeMarkdown function in the Pdf2MdUtil.java utility class located at yudao-module-digitalcourse/yudao-module-digitalcourse-biz/src/main/java/cn/iocoder/yudao/module/digitalcourse/util/. The function fails to properly sanitize the fileUrl parameter, allowing attackers to craft malicious input containing directory traversal sequences such as ../ to escape the intended directory boundaries.

The vulnerability requires network access and high privileges to exploit. While the immediate confidentiality impact is limited, successful exploitation could allow attackers to read sensitive configuration files, credentials, or other protected resources on the target system. This product follows a rolling release model, so discrete version numbers for affected and patched releases are unavailable.

Root Cause

The root cause of this vulnerability is improper input validation in the recognizeMarkdown function. The fileUrl argument is not adequately sanitized to prevent path traversal sequences before being used in file operations. This allows an attacker to include relative path components like ../ or encoded variants to navigate outside the intended directory structure.

Attack Vector

The attack can be launched remotely over the network by an authenticated attacker with high privileges. The attacker manipulates the fileUrl parameter passed to the recognizeMarkdown function to include path traversal sequences. When the application processes this malicious input, it accesses files outside the intended directory, potentially exposing sensitive system files or application data.

The vulnerable code path processes PDF to Markdown conversions and reads files based on user-supplied URL input. Without proper path canonicalization and validation, the application follows the attacker-controlled path to arbitrary file locations. For detailed technical analysis, refer to the Feishu Document Link and VulDB CTI Report #351291.

Detection Methods for CVE-2026-4285

Indicators of Compromise

• Unusual file access patterns in application logs showing path traversal sequences (../, ..%2f, %2e%2e/)
• Access attempts to files outside the expected yudao-module-digitalcourse directory structure
• Requests to the recognizeMarkdown function with suspicious fileUrl parameter values
• Log entries indicating access to system files such as /etc/passwd, configuration files, or application secrets

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block path traversal sequences in request parameters
• Monitor application logs for anomalous file access patterns targeting the Pdf2MdUtil utility
• Deploy intrusion detection signatures for common path traversal payloads targeting Java applications
• Review access logs for requests containing encoded traversal sequences targeting the fileUrl parameter

Monitoring Recommendations

• Enable verbose logging for the yudao-module-digitalcourse component to capture all file access operations
• Set up alerts for any file access attempts outside the designated working directories
• Monitor for unusual API request patterns to endpoints utilizing the recognizeMarkdown functionality
• Implement file integrity monitoring on sensitive configuration and data directories

How to Mitigate CVE-2026-4285

Immediate Actions Required

• Review and restrict access to the recognizeMarkdown functionality to only trusted administrators
• Implement additional network-level access controls to limit exposure of the affected component
• Deploy WAF rules to block path traversal attempts targeting the fileUrl parameter
• Audit existing access logs for potential exploitation attempts

Patch Information

The vendor (taoofagi) was contacted about this vulnerability but did not respond. As easegen-admin uses a rolling release model, users should monitor the project repository for any commits addressing path traversal issues in the Pdf2MdUtil.java file. Check for updates beyond commit 8f87936ac774065b92fb20aab55b274a6ea76433 that may include security fixes. Additional details are available via VulDB #351291.

Workarounds

• Implement server-side input validation to reject any fileUrl values containing path traversal sequences before processing
• Apply path canonicalization and ensure the resolved path remains within the expected base directory
• Use an allowlist approach for permitted file paths rather than a blocklist for traversal sequences
• Consider disabling the recognizeMarkdown functionality if not critical to operations until a patch is available

# Example input validation approach - add to application configuration
# Block common path traversal sequences at the web server level

# Apache mod_security rule example
SecRule ARGS "@contains ../" "id:1001,deny,status:403,msg:'Path Traversal Attempt'"
SecRule ARGS "@contains ..\\" "id:1002,deny,status:403,msg:'Path Traversal Attempt'"
SecRule ARGS "@contains %2e%2e" "id:1003,deny,status:403,msg:'Encoded Path Traversal'"