Vulnerability Details CVE-2026-58057
Flowise before 3.1.3 validates Custom MCP stdio environment variables against a denylist using a case-sensitive comparison, so on Windows, where environment names are case-insensitive, supplying 'node_options' bypasses the NODE_OPTIONS denylist entry. An authenticated user who can configure a Custom MCP node can thereby inject NODE_OPTIONS --require and execute arbitrary code in the Flowise server context.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 15.1%
CVSS Severity
CVSS v3 Score 5.0