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.

CVSS 4.0

5.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

CVSS 3.1

6.3CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

EPSS

0.3% chance of exploitation in the next 30 days; higher than 25% of CVEs (scores of 2026-10-25)

CWEs

CWE-183, CWE-942

Published

2026-07-24

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

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-via-binding

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