Vulnerability Description
Jan through 0.8.4, fixed in commit 3e1c1e7, contains a CORS misconfiguration vulnerability in its local API server that allows network-adjacent attackers to bypass trusted host restrictions by exploiting the server's replacement of user-configured trusted hosts with a wildcard that reflects arbitrary origins with credentials. Attackers on the local network or using DNS rebinding can reach the unauthenticated OpenAI-compatible API to perform inference, enumerate models, invoke MCP tools, and read cross-origin responses.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/janhq/jan/commit/3e1c1e724f696620d89bb4a9cc18a380e0753757
- https://github.com/janhq/jan/issues/8453
- https://github.com/janhq/jan/pull/8506
- https://www.vulncheck.com/advisories/jan-local-api-server-cors-origin-reflection
FAQ
What is CVE-2026-66005?
CVE-2026-66005 is a vulnerability with a CVSS score of 6.3 (MEDIUM). Jan through 0.8.4, fixed in commit 3e1c1e7, contains a CORS misconfiguration vulnerability in its local API server that allows network-adjacent attackers to bypass trusted host restrictions by exploit...
How severe is CVE-2026-66005?
CVE-2026-66005 has been rated MEDIUM with a CVSS base score of 6.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-66005?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.