What’s Vulnerable › Vulnerabilities

CVE-2026-66005: Jan Local API Server CORS Origin Reflection via 0.0.0.0 Binding

• Severity: medium (CVSS 6.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-24 · updated 2026-10-24
• Weakness: CWE-183

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.

Affected products

• janhq jan: through 0.8.4

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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