RCE in Flowiseai Flowise

CVE-2025-59528

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.

Vulnerability class: RCE (Remote Code Execution)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.862 (99.7th percentile), scored .

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-59528: held from 0.862 to 0.862.

EPSS over last 30 days · oldest: 0.862 · newest: 0.862 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-59528?
CVE-2025-59528 is a critical-severity vulnerability in Flowiseai Flowise, classified under Code Injection. CVSS score: 10.0/10. Published 2025-09-22.
How severe is CVE-2025-59528?
Critical severity. CVSS v3 base score is 10.0 out of 10.
Is CVE-2025-59528 known to be exploited?
18 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.