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.

CVSS 4.0

2.3CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

CVSS 3.1

5.0CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS

1.6% chance of exploitation in the next 30 days; higher than 75% of CVEs (scores of 2026-10-25)

CWE

CWE-178

Published

2026-06-28

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Affected

• flowiseai:flowise

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

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