CVE-2026-58057

Description

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.

CVSS Vector

References

• https://github.com/FlowiseAI/Flowise/pull/6471
• https://github.com/bikini/exploitarium/tree/main/flowise-mcp-env-case-bypass-poc
• https://www.vulncheck.com/advisories/flowise-custom-mcp-environment-variable-denylist-bypass-via-case-sensitivity