Vulnerability Description
Ouroboros is a local-first runtime for AI coding agents that records their actions and applies user-defined policies to constrain behavior. Versions prior to 0.42.1 have an incomplete denylist. Several execution-routing keys of the same RCE class were omitted, so a malicious cloned repo can still reach arbitrary command execution by shipping a .env (auto-loaded at import, with no review step). The CVE-2026-47211 fix added _UNTRUSTED_ENV_DENYLIST to stop an untrusted project-directory .env from redirecting execution, but it did not account for all keys. The backend config-home and MCP/plugin roots bypass the approval gate by pointing the nested agent, MCP servers, and plugin roster at attacker config. Other variables re-enable blocked local transports, replace sub-agent prompts, switch backends, and lower tool approval classes, further weakening the approval gate. This issue has been fixed in version 0.42.1.
Related Weaknesses (CWE)
References
- https://github.com/Q00/ouroboros/releases/tag/v0.42.1
- https://github.com/Q00/ouroboros/security/advisories/GHSA-jv2h-4p9v-wf5w
FAQ
What is CVE-2026-66065?
CVE-2026-66065 is a documented vulnerability. Ouroboros is a local-first runtime for AI coding agents that records their actions and applies user-defined policies to constrain behavior. Versions prior to 0.42.1 have an incomplete denylist. Severa...
How severe is CVE-2026-66065?
CVSS scoring is not yet available for CVE-2026-66065. Check NVD for updates.
Is there a patch for CVE-2026-66065?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.