CVE-2026-66065: Ouroboros is a local-first runtime for AI coding agents that records their actions and applies user-defined policies to

Ouroboros, a local-first runtime for AI coding agents that enforces security policies, had a vulnerability in versions before 0.42.1 where its denylist (a list of blocked actions) was incomplete. A malicious cloned repository could bypass security controls by using environment variables (configuration settings stored in a .env file) that weren't on the denylist, allowing arbitrary command execution (RCE, where an attacker runs commands on a system they don't own). The vulnerability existed because previous fixes missed several environment variable keys that could be exploited to weaken or bypass the approval system.