Path Traversal in Haris-Musa Excel-Mcp-Server
CVE-2026-85661
excel-mcp-server 0.1.8 fails to enforce path confinement in stdio mode when EXCEL_FILES_PATH is unset, allowing attackers to read and write arbitrary files. Attackers can supply unchecked file paths to read and write tools to access any file accessible to the process.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.007 (51.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.002
Affected products
Weakness classification (CWE)
References
- github.com/haris-musa/excel-mcp-server (product)
- github.com/haris-musa/excel-mcp-server/blob/v0.1.8/src/excel_mcp/server.py (technical-description)
- github.com/haris-musa/excel-mcp-server/blob/v0.1.8/src/excel_mcp/validation.py (technical-description)
- github.com/haris-musa/excel-mcp-server/issues/149 (issue-tracking)
- www.vulncheck.com/advisories/excel-mcp-server-0.1.8-arbitrary-file-read-write-v… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-85661?
- CVE-2026-85661 is a critical-severity vulnerability in Haris-Musa Excel-Mcp-Server, classified under Path Traversal. CVSS score: 9.8/10. Published 2026-09-04.
- How severe is CVE-2026-85661?
- Critical severity. CVSS v3 base score is 9.8 out of 10.