CVE-2026-85661

critical

Description

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.

References

https://www.vulncheck.com/advisories/excel-mcp-server-0.1.8-arbitrary-file-read-write-via-stdio-mode

https://github.com/haris-musa/excel-mcp-server/issues/149

https://github.com/haris-musa/excel-mcp-server/blob/v0.1.8/src/excel_mcp/validation.py

https://github.com/haris-musa/excel-mcp-server/blob/v0.1.8/src/excel_mcp/server.py

https://github.com/haris-musa/excel-mcp-server

Details

Source: Mitre, NVD

Published: 2026-09-04

Updated: 2026-09-14

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 9.3

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Severity: Critical

EPSS

EPSS: 0.00441