CVE-2026-40576 Details
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.
A path traversal vulnerability has been identified in excel-mcp-server versions through 0.1.7. This vulnerability allows an unauthenticated attacker to read, write, and overwrite arbitrary files on the host filesystem. The issue arises when the server is running in SSE or Streamable-HTTP transport mode, the default for remote use. The vulnerability exploits flaws in the get_excel_path() function, which fails to properly validate filepath arguments, bypassing intended file operation restrictions. The server's default settings further facilitate exploitation by exposing the service to all network interfaces without authentication.
Users can upgrade to excel-mcp-server version 0.1.8, which addresses the path traversal vulnerability by implementing proper filepath validation in the get_excel_path() function.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Apr 21, 2026CISA-ADP
Assessed Apr 21, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/haris-musa/excel-mcp-server/security/advisories/GHSA-j98m-w3xp-9f56 | CISA-ADP | AdvisoryExploitRemedyVendor |
| https://github.com/haris-musa/excel-mcp-server/security/advisories/GHSA-j98m-w3xp-9f56 | [email protected] | AdvisoryExploitRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-22 | Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| excel-mcp-server | All versions |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 21, 2026 | New CVE Received | [email protected] |
| Apr 21, 2026 | CVE Modified | CISA-ADP |