CVE-2026-66005 Jan Local API Server CORS Origin Reflection via 0.0.0.0 Binding
Network-adjacent attackers can bypass CORS restrictions to access the local API, read data, and invoke tools via DNS rebinding or local network access.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-66005?
CVE-2026-66005 is a medium-severity vulnerability in janhq jan, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Which versions are affected by CVE-2026-66005?
How do I fix CVE-2026-66005?
No fix has been published for CVE-2026-66005 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-66005 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66005 exists.
Sources
Also known as GHSA-4r96-7xrx-4gcr.