CVE-2026-49471: Serena: Unauthenticated Flask dashboard on fixed port enables DNS rebinding → memory poisoning → RCE

Serena’s built-in web dashboard exposes an unauthenticated Flask API on a fixed, predictable port (TCP 24282, hardcoded as 0x5EDA in constants.py). The server has no authentication, no CSRF protection, and no Host header validation. A DNS rebinding attack allows a malicious webpage to reach this API from any browser and write arbitrary content to the agent’s persistent memory store — which the agent reads and acts on autonomously. Combined with execute_shell_command (enabled by default in all contexts via shell=True), this creates a full remote code execution chain requiring only that the victim visit a malicious webpage while Serena is running.