OS Command Injection in Flowise - #VU146557
Published: September 1, 2026
Vulnerability identifier: #VU146557
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-78
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to improper neutralization of special elements used in an os command in the CustomMCP and SupergatewayMCP command validation logic when the server is started with CUSTOM_MCP_SECURITY_CHECK=false and a custom MCP node is executed. A remote user can configure a custom MCP node to run arbitrary commands to execute arbitrary code.
Exploitation requires the CUSTOM_MCP_SECURITY_CHECK environment setting to be disabled.
Affected software
Flowise
Remediation
Install security update from vendor's website.
Flowise - update to 3.1.4