CVE-2026-66005

Jan Local API Server CORS Origin Reflection via 0.0.0.0 Binding

MEDIUM
6.3
CVSS Score
Published: July 24, 2026 at 02:57 PM UTC
Updated: October 24, 2026 at 01:10 PM UTC
1 product affected across 1 vendorJan

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Severity
MEDIUM6.3
Exploit prediction
EPSS 0.3%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0 ≤ v ≤ 0.8.40
Vendor states this is fixed in 3e1c1e724f696620d89bb4a9cc18a380e0753757 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.3MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-183CWE-942

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