{"cve":"CVE-2026-55582","nvd":{"published":"2026-08-25T16:16:55.650","modified":"2026-09-09T21:07:31.353","status":"Deferred","description":"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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.4},"cwes":["CWE-78"],"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"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-55582","score":0.00267,"percentile":0.18913,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-74hp-mggr-hv58","url":"https://osv.dev/vulnerability/GHSA-74hp-mggr-hv58","summary":"mcp-shell has a Secure Mode Allowlist Bypass via Git Shell Alias","modified":"2026-08-26T15:41:19.235688282Z","packages":[{"ecosystem":"Go","name":"github.com/sonirico/mcp-shell","purl":"pkg:golang/github.com/sonirico/mcp-shell","ranges":["<0.6.0"],"fixed":["0.6.0"]}]},{"id":"GO-2026-6291","url":"https://osv.dev/vulnerability/GO-2026-6291","summary":"mcp-shell has a Secure Mode Allowlist Bypass via Git Shell Alias in github.com/sonirico/mcp-shell","modified":"2026-08-26T15:30:06.160904784Z","packages":[{"ecosystem":"Go","name":"github.com/sonirico/mcp-shell","purl":"pkg:golang/github.com/sonirico/mcp-shell","ranges":["<0.6.0"],"fixed":["0.6.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}