CVSS 4.0
8.6 highCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NCVE-2026-55580
High (8.6). EPSS 0.2% chance of exploitation in the next 30 days. Fixed in github.com/sonirico/mcp-shell 0.6.0.
mcp-shell is an MCP server for running shell commands securely, auditably, and on demand. Prior to 0.6.0, config.go initializes Security.Enabled to false, and when MCP_SHELL_SEC_CONFIG_FILE is unset, main.go starts the documented bare-binary deployment without a security policy. SecurityValidator.validateCommand in security.go then short-circuits and allows every command supplied to the shell_exec MCP tool, so an LLM connected over stdio can execute unrestricted OS commands as the mcp-shell process user. The README from-source installation and MCP client configuration omit MCP_SHELL_SEC_CONFIG_FILE, making the insecure state the documented default. This issue is fixed in version 0.6.0.
Severity
- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 9% of CVEs (scores of 2026-10-31)
- CWE
- CWE-78
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-f5pj-2738-996m | Go | github.com/sonirico/mcp-shell | <0.6.0 | 0.6.0 |
| GO-2026-6292 | Go | github.com/sonirico/mcp-shell | <0.6.0 | 0.6.0 |
References
- https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09f
- https://github.com/sonirico/mcp-shell/pull/16
- https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0
- https://github.com/sonirico/mcp-shell/security/advisories/GHSA-f5pj-2738-996m
- https://github.com/sonirico/mcp-shell/security/advisories/GHSA-f5pj-2738-996m