CVSS 3.1
8.4 highCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVE-2026-55581
High (8.4). EPSS 0.5% 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, the default Docker security.yaml includes /bin/bash in allowed_executables, while security.go validates only the first token and checkBlockedPatternsAndCommands does not reject the shell command-mode flag -c. A caller of the shell_exec MCP tool can provide the command argument `/bin/bash -c <arbitrary-command>`, which passes validation and reaches executor.go, where parseCommand and exec.CommandContext execute the arbitrary command as mcpuser outside the intended allowlist. This issue is fixed in version 0.6.0.
Severity
- EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 39% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-78, CWE-183, CWE-1188
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-3x77-wg38-92r3 | Go | github.com/sonirico/mcp-shell | <0.6.0 | 0.6.0 |
| GO-2026-6290 | 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-3x77-wg38-92r3
- https://github.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3