CVE-2026-73601 PUBLISHED

Flowise before 3.1.3 Remote Code Execution via Custom MCP

Assigner: VulnCheck
Reserved: 13.08.2026 Published: 13.08.2026 Updated: 13.08.2026

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.

Metrics

CVSS 4.0

CVSS 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
CVSS Score: 9

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	High
Attack Complexity	Low	Integrity	High	Integrity	High
Attack Requirements	Present	Availability	High	Availability	High
Privileges Required	Low
User Interaction	None

CVSS 4.0

Product Status

Vendor	FlowiseAI
Product	Flowise
Versions	Default: unaffected affected from 0 to 3.1.3 (excl.) Version 3.1.3 is unaffected

Vendor	FlowiseAI
Product	Flowise
Versions	Default: unaffected affected from 0 to 3.1.3 (excl.) Version 3.1.3 is unaffected

Credits

alex-elttam reporter

References

Problem Types

Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection') CWE