CVE-2025-71336: Flowise - Unsandboxed Remote Code Execution via Custom MCP

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-25 · updated 2026-10-12
Weakness: CWE-78

Description

Flowise before 3.0.6 (affected versions 2.2.7-patch.1 and earlier) contains an unsandboxed remote code execution vulnerability in the Custom MCP feature, which is designed to execute OS commands such as launching local MCP servers. Because Flowise's authentication and authorization model is minimal and lacks role-based access control, and the default installation runs without authentication unless FLOWISE_USERNAME and FLOWISE_PASSWORD are set, an attacker can send a crafted JSON payload with the header 'x-request-from: internal' to the /api/v1/node-load-method/customMCP endpoint to execute arbitrary OS commands, resulting in complete compromise of the platform container or server.

Affected products

FlowiseAI Flowise: before 3.0.6 — fixed in 3.0.6

How to fix

Upgrade to a fixed version: FlowiseAI Flowise 3.0.6. Check the vendor advisory for mitigations.

References

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