Relative Path Traversal Vulnerability in mcpo-simple-server

A relative path traversal vulnerability, identified as CVE-2026-7404, has been discovered in getsimpletool mcpo-simple-server up to version 0.2.0. The vulnerability resides within the delete_shared_prompt function of the src/mcpo_simple_server/services/prompt_manager/base_manager.py file. By manipulating the detail argument, a remote attacker can traverse the file system and delete arbitrary files. The vulnerability is remotely exploitable, and proof-of-concept exploit code is publicly available. The maintainers of the getsimpletool project have been notified of this vulnerability but have not yet responded. This poses a significant risk to systems running mcpo-simple-server, as it could lead to unauthorized file deletion and potential system compromise.

Attack Chain

1. The attacker identifies a vulnerable mcpo-simple-server instance running version 0.2.0 or earlier.
2. The attacker crafts a malicious HTTP request targeting the delete_shared_prompt function.
3. The malicious request includes a manipulated detail argument containing relative path traversal sequences (e.g., ../).
4. The server-side application processes the request and passes the manipulated detail argument to the delete_shared_prompt function.
5. The delete_shared_prompt function uses the attacker-controlled detail argument to construct a file path.
6. Due to the path traversal sequences, the resulting file path points to a location outside the intended directory.
7. The application attempts to delete the file at the attacker-specified location.
8. If permissions allow, the file is successfully deleted, leading to potential data loss or system instability.

Impact

Successful exploitation of this vulnerability allows an attacker to delete arbitrary files on the affected system. This can lead to data loss, application malfunction, or even complete system compromise, depending on the files targeted for deletion. Given the public availability of exploit code, systems running vulnerable versions of mcpo-simple-server are at immediate risk. The impact is especially severe if the targeted files are critical system files or application data.

Recommendation

• Upgrade mcpo-simple-server to a patched version that addresses CVE-2026-7404, if available from the vendor.
• Deploy the Sigma rule Detect Mcpo-Simple-Server Path Traversal Attempt to identify exploitation attempts in web server logs.
• Implement strict input validation and sanitization on the detail argument of the delete_shared_prompt function, if patching is not immediately feasible.
• Monitor web server logs for suspicious activity, such as requests containing path traversal sequences.
• Restrict file system permissions to limit the impact of successful path traversal attacks.