VulnerabilityReceived
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.
CRITICAL 9.3EPSS 0.44%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.44%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.44% probability · 37th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Source
- disclosure@vulncheck.com
References
- https://github.com/haris-musa/excel-mcp-server
- 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/blob/v0.1.8/src/excel_mcp/validation.py
- https://github.com/haris-musa/excel-mcp-server/issues/149
- https://www.vulncheck.com/advisories/excel-mcp-server-0.1.8-arbitrary-file-read-write-via-stdio-mode
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.