CVE-2026-58057

low

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.

References

https://www.vulncheck.com/advisories/flowise-custom-mcp-environment-variable-denylist-bypass-via-case-sensitivity

https://github.com/bikini/exploitarium/tree/main/flowise-mcp-env-case-bypass-poc

https://github.com/FlowiseAI/Flowise/pull/6471

Details

Source: Mitre, NVD

Published: 2026-06-28

Updated: 2026-06-28

Risk Information

CVSS v2

Base Score: 4.6

Vector: CVSS2#AV:N/AC:H/Au:S/C:P/I:P/A:P

Severity: Medium

CVSS v3

Base Score: 5

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

Severity: Medium

CVSS v4

Base Score: 2.3

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

Severity: Low