CVSS 3.1
8.4 highCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVE-2026-55582
High (8.4). EPSS 0.3% 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 security.yaml allows /usr/bin/git, while security.go omits ! from containsShellMetacharacters and containsDangerousShellConstructs and applies no per-executable argument policy. A caller of the shell_exec MCP tool can provide the command argument /usr/bin/git -c alias.pwn=!<arbitrary-command>, causing Git to create a shell alias and execute arbitrary OS commands as the mcp-shell process user. The default Docker image runs as mcpuser with Git installed and secure mode enabled, so the bypass is exploitable in the default deployment without additional authentication beyond MCP connectivity. This issue is fixed in version 0.6.0.
Severity
- EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 18% 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-74hp-mggr-hv58 | Go | github.com/sonirico/mcp-shell | <0.6.0 | 0.6.0 |
| GO-2026-6291 | 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-74hp-mggr-hv58
- https://github.com/sonirico/mcp-shell/security/advisories/GHSA-74hp-mggr-hv58