Is CVE-2026-58057 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-58057?

CVE-2026-58057 has a CVSS v3 severity of MEDIUM (5).

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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.