FlowiseAI Flowise up to 3.0.x /tmp/pwn os command injection

Summaryinfo

A vulnerability has been found in FlowiseAI Flowise up to 3.0.x and classified as critical. Affected is an unknown function of the file /tmp/pwn. This manipulation causes os command injection. This vulnerability appears as CVE-2026-40933. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in FlowiseAI Flowise up to 3.0.x and classified as critical. Affected by this vulnerability is an unknown part of the file /tmp/pwn. The manipulation with an unknown input leads to a os command injection vulnerability. The CWE definition for the vulnerability is CWE-78. 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. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-40933 since 04/15/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1202 for this issue.

Upgrading to version 3.1.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• FlowiseAI

Name

• Flowise

Version

• 3.0

Website

• Product: https://github.com/FlowiseAI/Flowise/

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Duplicate

• Submit #XXXXXX: Xxxxxxxxx Xxxxxxx <= X.x.xx Xx Xxxxxxx Xxxxxxxxx (xxx-xx) (by Eric-a)

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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