Critical 9.8Published Sep 4, 2026

CVE-2026-85661excel-mcp-server 0.1.8 Arbitrary File Read/Write via stdio mode

Updated under an hour ago (Oct 27, 2026, 9:23 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for haris-musa excel-mcp-server

Exploited in the last 30 days

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.

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-22
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Sep 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

haris-musa excel-mcp-server haris_musa:excel_mcp_server (from the name)	through 0.1.8	CNA record

References

References

https://github.com/haris-musa/excel-mcp-server/issues/149	issue-tracking
https://github.com/haris-musa/excel-mcp-server	product
https://github.com/haris-musa/excel-mcp-server/blob/v0.1.8/src/excel_mcp/server.py	technical-description
https://github.com/haris-musa/excel-mcp-server/blob/v0.1.8/src/excel_mcp/validation.py	technical-description
https://www.vulncheck.com/advisories/excel-mcp-server-0.1.8-arbitrary-file-read-write-via-stdio-mode	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.