CVE-2026-7404: mcpo-simple-server Path Traversal Flaw

CVE-2026-7404 Overview

A path traversal vulnerability has been identified in getsimpletool mcpo-simple-server versions up to 0.2.0. The vulnerability exists in the delete_shared_prompt function located in src/mcpo_simple_server/services/prompt_manager/base_manager.py. Through manipulation of the detail argument, an attacker can achieve relative path traversal, potentially allowing unauthorized file system access. This vulnerability can be exploited remotely without authentication.

Critical Impact

Remote attackers can exploit this path traversal vulnerability to access or delete files outside the intended directory structure, potentially compromising system integrity and data confidentiality.

Affected Products

• getsimpletool mcpo-simple-server versions up to 0.2.0

Discovery Timeline

• 2026-04-29 - CVE CVE-2026-7404 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-7404

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 prompt management service of mcpo-simple-server, specifically within the delete_shared_prompt function in base_manager.py.

The vulnerable function fails to properly sanitize user-supplied input in the detail parameter before using it to construct file paths. This allows attackers to inject path traversal sequences (such as ../) to escape the intended directory boundary and access or manipulate files in arbitrary locations on the file system.

The vulnerability has been publicly disclosed through a GitHub Issue Discussion, and exploit information has been made available. The project maintainers were notified early through an issue report but have not yet responded.

Root Cause

The root cause of this vulnerability is insufficient input validation and sanitization in the delete_shared_prompt function. The detail argument is used directly in file path construction without proper validation to ensure it does not contain path traversal sequences. The application fails to canonicalize the path or verify that the resolved path remains within the expected directory structure.

Attack Vector

The vulnerability can be exploited remotely over the network. An attacker can craft malicious requests containing path traversal sequences in the detail parameter when invoking the delete_shared_prompt functionality. By including sequences like ../ in the input, an attacker can navigate outside the intended prompt storage directory and potentially:

• Delete arbitrary files on the system that the application has write permissions for
• Access sensitive configuration files or application data
• Disrupt service availability by removing critical application files

The attack does not require authentication or user interaction, making it particularly accessible to remote attackers. For additional technical details, refer to the VulDB Vulnerability #360140 entry.

Detection Methods for CVE-2026-7404

Indicators of Compromise

• HTTP requests containing path traversal sequences (../, ..%2f, %2e%2e/) in parameters related to prompt deletion functionality
• Unexpected file access or deletion events outside the application's designated directories
• Application logs showing attempts to access files with normalized paths outside expected boundaries

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block requests containing path traversal patterns
• Implement application-level logging for all file operations in the prompt manager service
• Monitor for anomalous file system activity, particularly deletions in directories outside the application scope
• Use SIEM solutions to correlate network requests with file system events

Monitoring Recommendations

• Enable verbose logging for the mcpo-simple-server prompt management functionality
• Set up alerts for file operations involving paths that resolve outside expected directories
• Monitor network traffic for requests to prompt-related endpoints containing suspicious path patterns
• Regularly audit file system permissions to ensure the application runs with minimal required privileges

How to Mitigate CVE-2026-7404

Immediate Actions Required

• Review and restrict network access to the affected mcpo-simple-server instances
• Implement input validation at the application or reverse proxy level to reject requests containing path traversal sequences
• Consider disabling the delete_shared_prompt functionality until a patch is available
• Apply the principle of least privilege to the application's file system permissions

Patch Information

As of the last update, no official patch has been released by the project maintainers. The vulnerability was reported through a GitHub issue, but the project has not yet responded. Users should monitor the GitHub Project Repository for updates and potential fixes.

Workarounds

• Implement a reverse proxy or WAF that filters requests containing path traversal sequences before they reach the application
• Restrict network access to the mcpo-simple-server to trusted sources only using firewall rules
• Run the application in a containerized or sandboxed environment to limit the impact of potential path traversal exploitation
• Apply file system permissions to prevent the application from accessing sensitive directories

# Example: Block access to mcpo-simple-server from untrusted networks using iptables
# Allow only trusted IP range (adjust as needed)
iptables -A INPUT -p tcp --dport 8080 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP