{"answers":{"affected":"3 open source packages ship an affected version, including github.com/sonirico/mcp-shell.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55581 exists.","fix":"Upgrade github.com/sonirico/mcp-shell to 0.6.0 or later.","what":"CVE-2026-55581 is a high-severity command injection vulnerability in sonirico mcp-shell, published on 25 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-55581 and fix it if it is affected.\n\nWhat it is: CVE-2026-55581 is a high-severity command injection vulnerability in sonirico mcp-shell, published on 25 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55581 exists.\n\nAffected packages and fixed versions:\n- github.com/sonirico/mcp-shell (Go): affected all versions; fixed in 0.6.0\n- github.com/sonirico/mcp-shell (Go): affected all versions; fixed in 0.6.0\n- github.com/sonirico/mcp-shell (Go): affected all versions; fixed in 0.6.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-55581/ (Markdown: https://insights.sbomify.com/CVE-2026-55581/index.md)","id":"CVE-2026-55581","markdown":"https://insights.sbomify.com/CVE-2026-55581/index.md","name":"CVE-2026-55581","record":{"aliases":["GHSA-3x77-wg38-92r3","GO-2026-6290"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Go MCP server","requires_auth":"none","summary":"Attackers can bypass the executable allowlist in mcp-shell by invoking /bin/bash with the -c flag, allowing arbitrary command execution.","user_interaction":"not_required","vuln_class":"command_injection"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":8.4,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-78","name":"Improper Neutralization of Special Elements used in an OS Command"},{"id":"CWE-183","name":"Permissive List of Allowed Inputs"},{"id":"CWE-1188","name":"Initialization of a Resource with an Insecure Default"}],"description":"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 \u003carbitrary-command\u003e`, 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.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"mcp-shell: Secure Mode Allowlist Bypass via Default `/bin/bash` Executable","id":"CVE-2026-55581","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"command_injection","year":"2026"},"n_packages":3,"n_references":4,"next":{"headline":"mcp-shell: Secure Mode Allowlist Bypass via Git Shell Alias","id":"CVE-2026-55582"},"packages":[{"ecosystem":"Go","fixed":["0.6.0"],"introduced":["0"],"last_affected":[],"package":"github.com/sonirico/mcp-shell","purl":null,"source":"GHSA-3x77-wg38-92r3"},{"ecosystem":"Go","fixed":["0.6.0"],"introduced":["0"],"last_affected":[],"package":"github.com/sonirico/mcp-shell","purl":"pkg:golang/github.com/sonirico/mcp-shell","source":"GHSA-3x77-wg38-92r3"},{"ecosystem":"Go","fixed":["0.6.0"],"introduced":["0"],"last_affected":[],"package":"github.com/sonirico/mcp-shell","purl":"pkg:golang/github.com/sonirico/mcp-shell","source":"GO-2026-6290"}],"prev":{"headline":"mcp-shell — Security Disabled by Default in Bare-Binary Deploy Path + Shell Interpreter in Secure-Mode Allowlist","id":"CVE-2026-55580"},"products":["mcp-shell"],"published":"2026-08-25","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-08-25","vendors":["sonirico"]},"summary":"Attackers can bypass the executable allowlist in mcp-shell by invoking /bin/bash with the -c flag, allowing arbitrary command execution.","url":"https://insights.sbomify.com/CVE-2026-55581/"}