---
id: CVE-2026-73601
title: >-
  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…
summary: >-
  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…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-95
vendor: flowiseai
product: flowise
affected:
  - flowise < 3.1.3
patched:
  - flowise 3.1.3
published: '2026-08-13'
updated: '2026-09-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73601'
references:
  - url: >-
      https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-g98q-rm45-q9h8
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/flowise-before-remote-code-execution-via-custom-mcp
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00883
epssPercentile: 0.57677
ingestedAt: '2026-09-05T15:41:17.287Z'
---

## Overview

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.

## Affected

- `flowise < 3.1.3`

## Remediation

Upgrade past the affected range:

- `flowise 3.1.3`