CVE-2026-91931 [HIGH] – Flowise before 3.1.4 contains a remote code execution vulnerability in the Custom MCP node

Flowise before 3.1.4 contains a remote code execution vulnerability in the Custom MCP node that allows authenticated attackers to execute arbitrary code by supplying npx package names in the mcpServerConfig parameter. Attackers can invoke npx with attacker-controlled npm packages to execute code on the Flowise server.