CVE-2026-40933: exploitation status and patch state
CVE-2026-40933 · CVSS 9.9 CRITICAL · EPSS 13%
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.
Is CVE-2026-40933 exploited?
Not in the CISA KEV catalog.
EPSS puts exploitation in the next 30 days at 13%.
Public exploit code: none found in monitored sources.
Which products and versions are affected?
No affected package list recorded here yet.
Is there a patch?
No patch identifier recorded here yet.
What PlainSec published about CVE-2026-40933
PlainSec has not published a story about this CVE.