Vulnerability 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 Score
MEDIUM
Related Weaknesses (CWE)
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-den
FAQ
What is CVE-2026-58057?
CVE-2026-58057 is a vulnerability with a CVSS score of 5.0 (MEDIUM). 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...
How severe is CVE-2026-58057?
CVE-2026-58057 has been rated MEDIUM with a CVSS base score of 5.0/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-58057?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.