CVE-2026-66005
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.
- Score
- CVSS 3.1 6.3 Medium
- Status
- Deferred - disclosure@vulncheck.com
- Published
- 2026-07-24
- Last modified
- 2026-10-24
- Weaknesses
- CWE-183, CWE-942
Affected products
References
- https://github.com/janhq/jan/issues/8453
- https://github.com/janhq/jan/pull/8506
- https://github.com/janhq/jan/commit/3e1c1e724f696620d89bb4a9cc18a380e0753757
- https://www.vulncheck.com/advisories/jan-local-api-server-cors-origin-reflection-via-binding
