CVE-2026-66005: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-4r96-7xrx-4gcr
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CVSS 6.3
CWE-183
Published
Advisory Summary

CVE-2026-66005 is a MODERATE (CVSS 6.3) security vulnerability vulnerability (CWE-183: Permissive List of Allowed Inputs) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are explicitly allowed by policy because the inputs are assumed to be safe, but the list is too permissive - that is, it allows an input that is unsafe, leading to resultant weaknesses.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-66005 at a Glance

CVE Identifier CVE-2026-66005
GHSA Identifier GHSA-4r96-7xrx-4gcr
Severity MODERATE
CVSS v3.1 Base Score 6.3
CWE Classification CWE-183: Permissive List of Allowed Inputs
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability Low (A:L)

How to Fix CVE-2026-66005

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-66005, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-183: Permissive List of Allowed Inputs, where the product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are explicitly allowed by policy because the inputs are assumed to be safe, but the list is too permissive - that is, it allows an input that is unsafe, leading to resultant weaknesses. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

References

NVD — CVE-2026-66005 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-66005
Software Source Repository REPOSITORY
https://github.com/janhq/jan/issues/8453
Software Source Repository REPOSITORY
https://github.com/janhq/jan/pull/8506
Security Fix Commit FIX COMMIT
https://github.com/janhq/jan/commit/3e1c1e724f696620d89bb4a9cc18a380e0753757
www.vulncheck.com/advisories/jan-loca... WEB
https://www.vulncheck.com/advisories/jan-local-api-server-cors-origin-reflection-via-binding

Frequently Asked Questions

What is CVE-2026-66005?
CVE-2026-66005 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-183: Permissive List of Allowed Inputs.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-66005?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-66005?
CVE-2026-66005 has a CVSS v3.1 base score of 6.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L.
What CWE is associated with CVE-2026-66005?
CVE-2026-66005 is classified under CWE-183: Permissive List of Allowed Inputs (The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are explicitly allowed by policy because the inputs are assumed to be safe, but the list is too permissive - that is, it allows an input that is unsafe, leading to resultant weaknesses.).
How can I check Maven dependencies for CVE-2026-66005?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4r96-7xrx-4gcr",
  "modified" : "2026-07-24T15:33:03Z",
  "published" : "2026-07-24T15:33:03Z",
  "aliases" : [ "CVE-2026-66005" ],
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L"
  }, {
    "type" : "CVSS_V4",
    "score" : "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-66005"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/janhq/jan/issues/8453"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/janhq/jan/pull/8506"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/janhq/jan/commit/3e1c1e724f696620d89bb4a9cc18a380e0753757"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/jan-local-api-server-cors-origin-reflection-via-binding"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-183" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-07-24T15:19:07Z"
  }
}