What is the CVSS score of CVE-2026-66005?

CVE-2026-66005 has a CVSS 4.0 base score of 5.3 (Medium). 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. EPSS exploitation probability: 0.2%.

Is there a public PoC exploit available for CVE-2026-66005?

Yes, a public proof-of-concept exploit is available for CVE-2026-66005. Prioritise patching immediately. EPSS: 0.2%.

Is there a patch available for CVE-2026-66005?

Yes, a patch is available for CVE-2026-66005. Update the affected software to the latest version immediately.

Jan CVE-2026-66005

EUVD-2026-48611 MEDIUM

Permissive List of Allowed Inputs (CWE-183)

2026-07-24 VulnCheck

GHSA-4r96-7xrx-4gcr

Authentication Bypass Jan

5.3

CVSS 4.0 · Vendor: VulnCheck

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Vulnerability Assessment

Weakness

CWE

CWE-183

OWASP Top 10:2025

A06:2025 - Insecure Design

ASVS 5.0

V2 - Validation and Business Logic Strict input allowlisting

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 27, 2026

A CORS misconfiguration in Jan up to version 0.8.4 allows network-adjacent attackers to bypass trusted host restrictions when the server is bound to 0.0.0.0, enabling unauthorized access to the OpenAI-compatible API for model enumeration, inference, and MCP tool invocation. A publicly available exploit exists, and CISA KEV does not list active exploitation; EPSS score is low at 0.19%, indicating limited real-world exploitation risk.

Affected VersionsENISA

jan 0 ≤0.8.4

Affected Packages

euvd jan no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulnCheck) PRIMARY 5.3 MEDIUM

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

Primary rating from Vendor (VulnCheck) · only source for this CVE.

CVSS VectorVendor: VulnCheck

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

None

User Interaction

Passive

Vulnerable system: Confidentiality

Low

Vulnerable system: Integrity

Low

Vulnerable system: Availability

Low

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

DescriptionCVE.org

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.

Threat Intelligence Overview

EPSS Score

0.2%

Top 91% exploitable

Exploit

POC

Public exploit code exists

Data Quality

7 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS

Vulnrichment

GitHub

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC Yes

EPSS 0.2%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.