CVE-2026-73601

critical

Description

Flowise versions before 3.1.3 contain a remote code execution vulnerability in the Custom MCP node when CUSTOM_MCP_PROTOCOL is set to stdio, allowing authenticated users to execute arbitrary commands by manipulating environment variables and command arguments. Attackers can abuse PYTHONWARNINGS and BROWSER environment variables with python3, or leverage the root working directory with node to bypass validation and execute system commands.

References

https://www.vulncheck.com/advisories/flowise-before-remote-code-execution-via-custom-mcp

https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-g98q-rm45-q9h8

Details

Source: Mitre, NVD

Published: 2026-08-13

Updated: 2026-08-13

Risk Information

CVSS v2

Base Score: 9

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

Severity: High

CVSS v3

Base Score: 8.8

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

Severity: High

CVSS v4

Base Score: 9

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

Severity: Critical