CVE-2026-108953
mac-shell-mcp before 2.0.0 contains an OS command injection vulnerability that allows MCP clients to bypass the command whitelist by injecting shell metacharacters into execute_command arguments.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.75%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
mac-shell-mcp before 2.0.0 contains an OS command injection vulnerability that allows MCP clients to bypass the command whitelist by injecting shell metacharacters into execute_command arguments. Attackers or malicious prompts can call a safe command such as pwd with arguments like ';' to run forbidden commands as the server user without approval.
- CVSS 4.0
- 8.5 HIGHCVSS:4.0/AV:L/AC:L/AT:N/PR:L/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
- 0.75% probability · 55th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-78
- Source
- disclosure@vulncheck.com
EPSS moved from 0.7% on 13 October 2026 to 0.7% on 26 October 2026.
References
- https://github.com/cfdude/mac-shell-mcp
- https://github.com/cfdude/mac-shell-mcp/blob/1c1708201abb7a18c83075e1bf933e7a92cbeb9f/src/services/command-service.ts#L257-L340
- https://github.com/cfdude/mac-shell-mcp/commit/932ce733cde07bb30b1f186303e6692dbb5d087a
- https://github.com/cfdude/mac-shell-mcp/issues/45
- https://www.vulncheck.com/advisories/mac-shell-mcp-before-2.0.0-os-command-injection-via-execute-command-arguments
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.