CVE-2026-73601: Flowiseai Flowise

High severity, CVSS 8.8. EPSS: 1.1% chance of exploitation in the next 30 days.

Flowise versions before 3.1.3 contain a remote code execution vulnerability in the Custom MCP node when CUSTOM_MCP_PROTOCOL is set to stdio, allowing authenticated users to execute arbitrary commands by manipulating environment variables and command arguments. Attackers can abuse PYTHONWARNINGS and BROWSER environment variables with python3, or leverage the root working directory with node to bypass validation and execute system commands.

Affected products

• Flowiseai Flowise: before 3.1.3 (fixed in 3.1.3)

Published 2026-08-13. Last modified 2026-09-04.