CVE-2026-40933: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in FlowiseAI Flowise
CVE-2026-40933 is a critical OS command injection vulnerability in FlowiseAI's Flowise product prior to version 3. 1. 0. It arises from unsafe serialization of stdio commands in the MCP adapter, allowing an authenticated attacker to add a malicious MCP stdio server with arbitrary commands. Despite input sanitization attempts, attackers can bypass these checks and execute arbitrary OS commands. This vulnerability is fixed in Flowise version 3. 1. 0.
AI Analysis
Technical Summary
FlowiseAI Flowise versions before 3.1.0 contain an OS command injection vulnerability (CWE-78) due to unsafe serialization of stdio commands in the MCP adapter. Authenticated users can add a new MCP stdio server with arbitrary commands via the Custom MCP configuration interface at http://localhost:3000/canvas. Input sanitization functions such as validateCommandInjection and validateArgsForLocalFileAccess, and a predefined safe command list, are insufficient to prevent injection. For example, the command 'npx' combined with execution arguments like '-c touch /tmp/pwn' enables arbitrary code execution on the host OS. The vulnerability is resolved in version 3.1.0.
Potential Impact
An authenticated attacker can execute arbitrary operating system commands on the host running Flowise prior to version 3.1.0. This can lead to complete compromise of confidentiality, integrity, and availability of the affected system, as reflected by the CVSS score of 10. The vulnerability allows code execution with the privileges of the Flowise process.
Mitigation Recommendations
Upgrade Flowise to version 3.1.0 or later, where this vulnerability is fixed. No official patch or temporary workaround is documented beyond upgrading. Since this is not a cloud service, remediation depends on user action to update the software.
CVE-2026-40933: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in FlowiseAI Flowise
Description
CVE-2026-40933 is a critical OS command injection vulnerability in FlowiseAI's Flowise product prior to version 3. 1. 0. It arises from unsafe serialization of stdio commands in the MCP adapter, allowing an authenticated attacker to add a malicious MCP stdio server with arbitrary commands. Despite input sanitization attempts, attackers can bypass these checks and execute arbitrary OS commands. This vulnerability is fixed in Flowise version 3. 1. 0.
CVSS v3.1
Score 10.0critical
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
FlowiseAI Flowise versions before 3.1.0 contain an OS command injection vulnerability (CWE-78) due to unsafe serialization of stdio commands in the MCP adapter. Authenticated users can add a new MCP stdio server with arbitrary commands via the Custom MCP configuration interface at http://localhost:3000/canvas. Input sanitization functions such as validateCommandInjection and validateArgsForLocalFileAccess, and a predefined safe command list, are insufficient to prevent injection. For example, the command 'npx' combined with execution arguments like '-c touch /tmp/pwn' enables arbitrary code execution on the host OS. The vulnerability is resolved in version 3.1.0.
Potential Impact
An authenticated attacker can execute arbitrary operating system commands on the host running Flowise prior to version 3.1.0. This can lead to complete compromise of confidentiality, integrity, and availability of the affected system, as reflected by the CVSS score of 10. The vulnerability allows code execution with the privileges of the Flowise process.
Mitigation Recommendations
Upgrade Flowise to version 3.1.0 or later, where this vulnerability is fixed. No official patch or temporary workaround is documented beyond upgrading. Since this is not a cloud service, remediation depends on user action to update the software.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-15T20:40:15.518Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e7e91619fe3cd2cdfaec46
Added to database: 4/21/2026, 9:16:06 PM
Last enriched: 4/29/2026, 11:42:59 AM
Last updated: 6/6/2026, 6:23:52 AM
Views: 246
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