SEPTEMBER 19, 2026
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Case File

CVE-2026-40933

CRITICAL · CVSS 9.9 EPSS 13.36% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-04-21 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 9.9. Public exploit code or proof-of-concept references have been detected in its references. Its EPSS score suggests a 13.4% probability of exploitation in the next 30 days. Exploitation may require the attacker to be authenticated.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
code execution
GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-40933
Severity
CRITICAL
CVSS
9.9
EPSS
13.36%

Original NVD 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.

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