Vulnerability in Janhq Jan
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.
EPSS: 0.002 (9.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L.
Affected products
- Janhq Jan — versions 0, 3e1c1e724f696620d89bb4a9cc18a380e0753757
Weakness classification (CWE)
References
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com (issue-tracking, technical-description, exploit)
- disclosure@vulncheck.com (issue-tracking, patch)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-66005?
- CVE-2026-66005 is a medium-severity vulnerability in Janhq Jan, classified under CWE-183. CVSS score: 6.3/10. Published 2026-07-24.
- How severe is CVE-2026-66005?
- Medium severity. CVSS v3 base score is 6.3 out of 10.