Description
Flowise is a drag & drop user interface to build a customized large language model flow. In version 3.0.5, Flowise is vulnerable to remote code execution. The CustomMCP node allows users to input configuration settings for connecting to an external MCP server. This node parses the user-provided mcpServerConfig string to build the MCP server configuration. However, during this process, it executes JavaScript code without any security validation. Specifically, inside the convertToValidJSONString function, user input is directly passed to the Function() constructor, which evaluates and executes the input as JavaScript code. Since this runs with full Node.js runtime privileges, it can access dangerous modules such as child_process and fs. This issue has been patched in version 3.0.6.
Affected products
flowiseai: flowise
References8
- github.com/FlowiseAI/Flowise/security/advisories/GHSA-3gcm-f6qx… ExploitVendor Advisory
- github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1… Product
- github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1… Product
- github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1… Product
- github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1… Product
- github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1… Product
- github.com/FlowiseAI/Flowise/blob/5930f1119c655bcf8d2200ae827a1… Product
- github.com/FlowiseAI/Flowise/releases/tag/flowise%403.0.6 Release Notes
Metrics
- CVSS 3.1
-
10.0
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - EPSS — exploit probability
- 87% percentile: 100 · as of 8 November 2026
- CWE
- CWE-94
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.