CVE-2026-40933

Aliases:GHSA-c9gw-hvqq-f33r
Received
Published: 21 Apr 2026, 21:00
Last modified:21 Apr 2026, 21:00

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
10 CRITICAL
v3.1 (cve.org)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

21 Apr 2026, 21:00
Published
Vulnerability first disclosed

Description

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, due to unsafe serialization of stdio commands in the MCP adapter, an authenticated attacker can add an MCP stdio server with an arbitrary command, achieving command execution. The vulnerability lies in a bug in the input sanitization from the “Custom MCP” configuration in http://localhost:3000/canvas - where any user can add a new MCP, when doing so - adding a new MCP using stdio, the user can add any command, even though your code have input sanitization checks such as validateCommandInjection and validateArgsForLocalFileAccess, and a list of predefined specific safe commands - these commands, for example "npx" can be combined with code execution arguments ("-c touch /tmp/pwn") that enable direct code execution on the underlying OS. This vulnerability is fixed in 3.1.0.

CVSS Metrics

  • v3.1•CRITICAL•Score: 9.9CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Techniques & Countermeasures

  • CWE-78•Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

    The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Affected Systems

  • flowiseai•flowise

    < 3.1.0

  • flowiseai•flowise-components

    < 3.1.0

  • Npm•flowise

    < 3.1.0

  • Npm•flowise-components

    < 3.1.0

References (4)