Is CVE-2026-40933 actively exploited?

No active exploitation of CVE-2026-40933 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-40933 be exploited remotely?

Yes. CVE-2026-40933 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-40933?

CVE-2026-40933 has a CVSS score of 9.9 (CRITICAL).

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CRITICAL

CVE-2026-40933

CWE-78Published: April 21, 2026· Updated: Apr 23, 2026

9.9

CVSS v3.1

EPSS:0.07%probability of exploitation in 30 daysPercentile:22.0th

Official 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.

NVD Source

Technical Analysis

CVE-2026-40933 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.9.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.