CVE-2026-40576: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in haris-musa excel-mcp-server
excel-mcp-server is a Model Context Protocol server for Excel file manipulation. A path traversal vulnerability exists in excel-mcp-server versions up to and including 0.1.7. When running in SSE or Streamable-HTTP transport mode (the documented way to use this server remotely), an unauthenticated attacker on the network can read, write, and overwrite arbitrary files on the host filesystem by supplying crafted filepath arguments to any of the 25 exposed MCP tool handlers. The server is intended to confine file operations to a directory set by the EXCEL_FILES_PATH environment variable. The function responsible for enforcing this boundary — get_excel_path() — fails to do so due to two independent flaws: it passes absolute paths through without any check, and it joins relative paths without resolving or validating the result. Combined with zero authentication on the default network-facing transport and a default bind address of 0.0.0.0 (all interfaces), this allows trivial remote exploitation. This vulnerability is fixed in 0.1.8.
AI Analysis
Technical Summary
The excel-mcp-server, a Model Context Protocol server for Excel file manipulation, suffers from a path traversal vulnerability (CWE-22) in versions up to 0.1.7. When operating in SSE or Streamable-HTTP transport mode, the server accepts crafted filepath arguments to any of its 25 MCP tool handlers without authentication. The function get_excel_path() intended to confine file operations to a directory defined by EXCEL_FILES_PATH fails due to two flaws: it allows absolute paths without checks and joins relative paths without resolving or validating them. Combined with default binding to 0.0.0.0 and no authentication, this enables trivial remote exploitation to access or modify arbitrary files. The vulnerability is fixed in version 0.1.8.
Potential Impact
An unauthenticated remote attacker can exploit this vulnerability to read, write, and overwrite arbitrary files on the host filesystem where excel-mcp-server is running. This can lead to information disclosure, data tampering, and potential denial of service. The CVSS 3.1 base score is 9.4 (critical), reflecting network attack vector, no required privileges or user interaction, and high impact on integrity and availability.
Mitigation Recommendations
A patch is available in excel-mcp-server version 0.1.8 that fixes the path traversal vulnerability. Users should upgrade to version 0.1.8 or later to remediate this issue. Since this is a cloud service, the vendor manages remediation for the hosted service; users should verify with the vendor that the service is updated. Until patched, restricting network access to the server and avoiding use of the vulnerable transport modes can reduce exposure.
CVE-2026-40576: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in haris-musa excel-mcp-server
Description
excel-mcp-server is a Model Context Protocol server for Excel file manipulation. A path traversal vulnerability exists in excel-mcp-server versions up to and including 0.1.7. When running in SSE or Streamable-HTTP transport mode (the documented way to use this server remotely), an unauthenticated attacker on the network can read, write, and overwrite arbitrary files on the host filesystem by supplying crafted filepath arguments to any of the 25 exposed MCP tool handlers. The server is intended to confine file operations to a directory set by the EXCEL_FILES_PATH environment variable. The function responsible for enforcing this boundary — get_excel_path() — fails to do so due to two independent flaws: it passes absolute paths through without any check, and it joins relative paths without resolving or validating the result. Combined with zero authentication on the default network-facing transport and a default bind address of 0.0.0.0 (all interfaces), this allows trivial remote exploitation. This vulnerability is fixed in 0.1.8.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The excel-mcp-server, a Model Context Protocol server for Excel file manipulation, suffers from a path traversal vulnerability (CWE-22) in versions up to 0.1.7. When operating in SSE or Streamable-HTTP transport mode, the server accepts crafted filepath arguments to any of its 25 MCP tool handlers without authentication. The function get_excel_path() intended to confine file operations to a directory defined by EXCEL_FILES_PATH fails due to two flaws: it allows absolute paths without checks and joins relative paths without resolving or validating them. Combined with default binding to 0.0.0.0 and no authentication, this enables trivial remote exploitation to access or modify arbitrary files. The vulnerability is fixed in version 0.1.8.
Potential Impact
An unauthenticated remote attacker can exploit this vulnerability to read, write, and overwrite arbitrary files on the host filesystem where excel-mcp-server is running. This can lead to information disclosure, data tampering, and potential denial of service. The CVSS 3.1 base score is 9.4 (critical), reflecting network attack vector, no required privileges or user interaction, and high impact on integrity and availability.
Mitigation Recommendations
A patch is available in excel-mcp-server version 0.1.8 that fixes the path traversal vulnerability. Users should upgrade to version 0.1.8 or later to remediate this issue. Since this is a cloud service, the vendor manages remediation for the hosted service; users should verify with the vendor that the service is updated. Until patched, restricting network access to the server and avoiding use of the vulnerable transport modes can reduce exposure.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-14T13:24:29.475Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Is Cloud Service
- true
Threat ID: 69e7a9cf19fe3cd2cde6d34d
Added to database: 4/21/2026, 4:46:07 PM
Last enriched: 4/21/2026, 5:01:16 PM
Last updated: 4/21/2026, 5:56:28 PM
Views: 5
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