Vulnerability Advisory : Flowise 3.1.4 SSRF Bypass via Custom Function Sandbox with LOW Attack Complexity

Flowise through 3.1.4 contains a server-side request forgery vulnerability that allows authenticated attackers with chatflows or agentflows create/update permissions to bypass the Custom Function sandbox's SSRF protection by requiring a module subpath inside an allowlisted package, such as axios/dist/node/axios.cjs or node-fetch/lib/index.js, which evades the vm2 mock table and returns an unwrapped HTTP client that skips the checkDenyList validation. Attackers can issue arbitrary GET and POST requests with attacker-controlled bodies via POST /api/v1/node-custom-function to reach loopback and internal-network addresses or the cloud metadata endpoint, enabling network mapping, credential disclosure, and state changes on internal services.