Vulnerability · Published Jun 23, 2026 · Assigned by VulnCheck
CVE-2026-56274Flowise - Remote Code Execution via MCP Security Bypass in validateCommandFlags and validateArgsForLocalFileAccess
Critical 9.9
In plain English
A critical-severity OS command injection in Flowise from Flowise. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 7.5% (higher than 95% of all known vulnerabilities). Ready-made attack tooling exists: Metasploit. Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | flowise | 3.1.2 | GHSA-m99r-2hxc-cp3q |
| npm | flowise-components | 3.1.2 | GHSA-m99r-2hxc-cp3q |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Flowise | Flowise | 0 – before 3.1.2 |
| Flowise | Flowise Components | 0 – before 3.1.2 |
Weakness: CWE-78 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H