Critical Flaw Exposes Flowise Systems to Remote Code Execution Attacks

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Remote Code Execution Vulnerability Disclosed in Flowise Ecosystem

A critical vulnerability in the Flowise ecosystem has been discovered, allowing remote code execution. The issue, identified as CVE-2026-40933, was initially reported in April 2026.

The Vulnerability Overview

Flowise, a widely used open-source platform for building Large Language Model (LLM) flows and AI agents, has over 52,000 GitHub stars and is a prominent component of various AI ecosystems relying on Anthropic’s MCP protocol.

According to experts, the root cause of the vulnerability lies within Anthropic’s MCP, a systemic command injection flaw that propagates throughout the ecosystem.

This allows an attacker to inject arbitrary commands, achieving code execution on the underlying operating system. The weakness existed prior to version 3.1.0 of Flowise, which permitted any user to add a new MCP and execute arbitrary code upon importing a crafted chatflow.

The Exploitation Method

The vulnerability can be exploited by convincing a user to import a custom MCP tool containing a malicious stdio MCP configuration. Upon import, the malicious command is executed, resulting in code execution on the server.

SUCCESSFUL EXPLOITATION OF CVE-2026-40933 GRANTS THE ATTACKER OS-LEVEL EXECUTION WITH THE FLOWISE PROCESS’S PRIVILEGES, OFTEN ROOT IN CONTAINERIZED DEPLOYMENTS, AND ACCESS TO EVERY CREDENTIAL STORED IN THE PLATFORM.

The Implications

Anthropic’s MCP is a critical component of the Flowise ecosystem, and its insecure implementation poses significant risks to users. While Flowise Cloud is not affected due to the disabling of stdio MCP, self-hosted instances remain vulnerable by default.

Researchers have provided proof-of-concept code demonstrating the exploit’s feasibility. The code creates a shell back to Docker’s bridge address for the host, showcasing the potential severity of the vulnerability.

The Recommendations

Experts emphasize the importance of addressing this vulnerability promptly, particularly considering the sensitive nature of the Flowise ecosystem and its widespread adoption in various industries.

Users are advised to update their Flowise installations to the latest version and implement additional security measures to mitigate potential risks.

Protect Yourself

Flowise users should prioritize updating their systems to the latest version and consider implementing additional security measures to minimize potential risks.