MediumVulnerabilityLLM-specific

CVE-2026-66005: Jan local API server CORS misconfiguration allows trusted host bypass

Source: NVD(opens in a new tab)
Identifier: CVE-2026-66005
Published: July 24, 2026
Record updated: October 9, 2026

Known exploitation: Not listed in the CISA Known Exploited Vulnerabilities catalog at the last check.
EPSS: 0.3%

Summary

CVE-2026-66005 affects Jan through 0.8.4 and is fixed in commit 3e1c1e7. The local API server has a CORS misconfiguration: it replaces user-configured trusted hosts with a wildcard that reflects arbitrary origins with credentials. Network-adjacent attackers, or attackers using DNS rebinding, can reach the unauthenticated OpenAI-compatible API to run inference, enumerate models, invoke MCP tools, and read cross-origin responses.

Mitigation

Fixed in commit 3e1c1e7.

Details

Scores and exploitation

CVSS score: 6.3(medium)
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
Attack vector: network
Attack complexity: low
Privileges required: none
User interaction: required
EPSS: 0.3%Estimated probability that this CVE is exploited in the next 30 days, from the FIRST Exploit Prediction Scoring System. Read on November 11, 2026.
Disclosure date: July 24, 2026

Weaknesses and techniques

Weakness (CWE): CWE-183
CWE-942

Classification

Attack type: Other
Attack sophistication: Moderate
AI component targeted: API
Impact: Confidentiality,
Integrity
Labels: security

How this record was produced

Summaries, mitigations and labels on this page are generated automatically from the source. The linked source is authoritative. The source gives this advisory a description and no title, so the title above is a headline generated from the source text.

Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-66005

First tracked: July 24, 2026 at 02:08 PM ET, from NVD/CVE Database

Classifier: claude-haiku-5-5, prompt v4

Classifier confidence: 90% (self-assessed)

Topics

Model Context Protocol

Summary

Mitigation

Topics

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