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

Flowise · Flowise Components

CVSS v4.0 VULNCHECK

8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 VULNCHECK

9.9 CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS

7.52% chance of exploitation in the next 30 days, 94th percentile

Published

2026-06-23

Updated

2026-06-24

Metasploit modules (1)

• rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/flowise_mcp_rce.rb

Security advisories

• FlowiseAI/Flowise/security/advisories/GHSA-m99r-2hxc-cp3q
• https://www.vulncheck.com/advisories/flowise-remote-code-execution-via-mcp-security-bypas…

References

• CVE Record
• NVD entry