CVE-2026-66005 MEDIUM

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

Vendor Janhq
Product jan
Weakness CWE-183
Published July 24, 2026
Last update July 24, 2026

CVSS base score

5.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction
Confidentiality
Integrity

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

July 24, 2026 CVE published
July 24, 2026 Record updated