CVE-2026-7205: papers-mcp-server Path Traversal Flaw

CVE-2026-7205 Overview

A path traversal vulnerability has been identified in duartium papers-mcp-server, specifically affecting the search_papers function within src/main.py. This vulnerability allows remote attackers to manipulate the topic argument to traverse directories and potentially access files outside the intended directory structure. The vulnerability was reported through a GitHub issue, but the project maintainers have not yet responded.

Critical Impact
Remote attackers can exploit this path traversal vulnerability to read arbitrary files on the server, potentially exposing sensitive configuration data, credentials, or other protected information.

Affected Products

duartium papers-mcp-server (commit 9ceb3812a6458ba7922ca24a7406f8807bc55598)

Discovery Timeline

2026-04-28 - CVE CVE-2026-7205 published to NVD
2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-7205

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as path traversal. The search_papers function in src/main.py fails to properly sanitize the topic parameter before using it in file path operations. This allows attackers to craft malicious input containing directory traversal sequences (such as ../) to escape the intended directory and access arbitrary files on the filesystem.

The exploit for this vulnerability has been publicly disclosed, increasing the risk of exploitation in the wild. Since the project maintainers have not responded to the vulnerability report, no official patch is currently available.

Root Cause

The root cause of this vulnerability is inadequate input validation in the search_papers function. The topic argument is used directly in file path construction without proper sanitization to strip or reject path traversal sequences. This is a common vulnerability pattern in applications that handle user-supplied input for file operations.

Attack Vector

The attack can be launched remotely over the network without requiring authentication. An attacker can send a specially crafted request to the MCP server with a malicious topic parameter containing path traversal sequences. For example, a topic value containing ../../../../etc/passwd could potentially allow the attacker to read sensitive system files.

The vulnerability mechanism involves insufficient validation of user-supplied path components in the search_papers function. When a malicious topic parameter is submitted, the function constructs a file path without properly sanitizing traversal sequences like ../. This allows attackers to escape the intended directory scope and access arbitrary files. For detailed technical analysis, see the VulDB entry and the GitHub issue report.

Detection Methods for CVE-2026-7205

Indicators of Compromise

Requests to the papers-mcp-server containing ../ or URL-encoded equivalents (%2e%2e%2f) in the topic parameter
Access logs showing unusual file paths or attempts to access system files like /etc/passwd or configuration files
Error logs indicating file access attempts outside the expected directory structure

Detection Strategies

Monitor web server and application logs for path traversal patterns in request parameters
Implement Web Application Firewall (WAF) rules to detect and block requests containing directory traversal sequences
Deploy SentinelOne Singularity platform to detect suspicious file access patterns and anomalous process behavior

Monitoring Recommendations

Enable detailed logging for the papers-mcp-server application to capture all incoming requests
Set up alerts for requests containing path traversal sequences or attempts to access sensitive file paths
Monitor for unexpected file reads from the server process, particularly outside the application directory

How to Mitigate CVE-2026-7205

Immediate Actions Required

Consider disabling or restricting access to the papers-mcp-server until a patch is available
Implement network-level access controls to limit which hosts can communicate with the MCP server
Deploy a Web Application Firewall (WAF) with rules to block path traversal attempts

Patch Information

No official patch is currently available from the project maintainers. The vulnerability was reported via a GitHub issue, but the project has not responded. Users should monitor the papers-mcp-server repository for updates.

Workarounds

Implement input validation at the application or reverse proxy level to reject requests containing ../ sequences
Use a reverse proxy to sanitize and validate all incoming requests before they reach the MCP server
Restrict the server process permissions using chroot, containers, or similar isolation mechanisms to limit the impact of path traversal attacks
Consider forking the repository and implementing input sanitization in the search_papers function until an official fix is released

bash

# Example: Implement path traversal blocking with nginx
location /api/ {
    # Block requests containing path traversal sequences
    if ($request_uri ~* "\.\.") {
        return 403;
    }
    proxy_pass http://localhost:8080;
}