High 8.4Published Aug 25, 2026

CVE-2026-55582mcp-shell: Secure Mode Allowlist Bypass via Git Shell Alias

Updated under an hour ago (2026-10-19 09:50 UTC)

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Every CVE for sonirico mcp-shell

Exploited in the last 30 days

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.

CVSS: 8.4 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-78
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Aug 28, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

sonirico mcp-shell sonirico:mcp_shell (from the name)	before 0.6.0	CNA record

References

https://github.com/sonirico/mcp-shell/security/advisories/GHSA-74hp-mggr-hv58x-refsource-confirm
https://github.com/sonirico/mcp-shell/pull/16x-refsource-misc
https://github.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09fx-refsource-misc
https://github.com/sonirico/mcp-shell/releases/tag/v0.6.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.