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CVE-2026-55581

8.4 · HIGH

mcp-shell is an MCP server for running shell commands securely, auditably, and on demand.

Published Aug 25, 2026CWE-78EPSS 0.45%

Overview

CVE-2026-55581 is a high-severity vulnerability. It was published on August 25, 2026 and has a CVSS 3.1 base score of 8.4 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.4, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical 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 <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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/sonirico/mcp-shell/commit/f31377fce6ec31114e5a4398c0e5270552bce09fGitHubgithub.com/sonirico/mcp-shell/pull/16GitHubgithub.com/sonirico/mcp-shell/releases/tag/v0.6.0GitHubgithub.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3GitHubgithub.com/sonirico/mcp-shell/security/advisories/GHSA-3x77-wg38-92r3

How CyberStrike helps

Frequently asked questions

What is CVE-2026-55581?

CVE-2026-55581 is a high-severity vulnerability. It was published on August 25, 2026 and has a CVSS 3.1 base score of 8.4 (HIGH).

How severe is CVE-2026-55581?

This vulnerability has a CVSS 3.1 base score of 8.4, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-55581?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-55581?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-55581 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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