CVE-2026-56274: Flowise - Remote Code Execution via MCP Security Bypass in validateCommandFlags and validateArgsForLocalFileAccess
Flowise before 3.1.2 contains multiple OS command injection vulnerabilities in the Custom MCP Server feature due to incomplete command-flag validation and a regex bypass in local file access restrictions. An attacker with a Flowise account of any role, or API access with view/update permissions for chatflows, can configure a malicious MCP server to bypass the validateCommandFlags blocklist (for example, 'docker build' is not blocked, and 'npx --yes' is not blocked while only '-y' is) and the validateArgsForLocalFileAccess checks, resulting in execution of arbitrary commands on the Flowise host.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Flowiseto a version that resolves this vulnerability.Fixed in 3.1.2
Event History
Frequently Asked Questions
What is the severity of CVE-2026-56274?
CVE-2026-56274 has a critical severity score of 9.9.
How do I fix CVE-2026-56274?
To fix CVE-2026-56274, upgrade to Flowise version 3.1.2 or later.
What are the consequences of exploiting CVE-2026-56274?
Exploiting CVE-2026-56274 can lead to remote code execution on the affected system.
Who is affected by CVE-2026-56274?
Any user with a Flowise account or API access with view/update permissions is affected by CVE-2026-56274.
What types of vulnerabilities are associated with CVE-2026-56274?
CVE-2026-56274 is associated with OS command injection vulnerabilities.