CVE-2026-56681

Description

9Router is an AI router & token saver. Prior to 0.5.6, 9Router deployments that allow requests to reach Next.js without the sanitizing custom-server.js wrapper trust the client-supplied X-9r-Real-Ip header in src/dashboardGuard.js when isLocalRequest decides whether canAccessPublicLlmApi may skip API-key validation for /api/v1/* routes. A remote unauthenticated attacker can set X-9r-Real-Ip to 127.0.0.1 and be classified as a local client, including on the verified GET /api/v1/models route. This permits unauthorized use of the instance owner's configured LLM providers, consumption of paid credits, and enumeration of configured providers and models. This issue is fixed in version 0.5.6.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: HIGH
CVSS score: 7.3 / 10
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Effective score: 7.3 / 10 HIGH source: CNA overview
CWE(s): CWE-807
Reserved: 2026-06-22
Published: 2026-09-22 16:02 UTC
Last updated: 2026-09-22 16:02 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/56xxx/CVE-2026-56681.json
Linked Threat: CVE-2026-56681 — 9Router: Authentication Bypass in Public LLM API via Spoofable X-9r-Real-Ip Header

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-22 16:17:48 UTC
NVD last modified: 2026-09-22 16:17:48 UTC
NVD CVSS v3.1: 7.3 / 10 HIGH source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Exploitability subscore: 3.9 / 10
Impact subscore: 3.4 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84541
Assigner: GitHub_M
Published: Sep 22, 2026, 4:02:25 PM
Updated: Sep 22, 2026, 4:02:25 PM
EUVD base score (CVSS 3.1): 7.3 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EUVD-reported EPSS: 0.0000
Vendors: decolua
Products: 9router (< 0.5.6)
Aliases: GHSA-5mj8-gf6m-fhw8

ENISA description: 9Router is an AI router & token saver. Prior to 0.5.6, 9Router deployments that allow requests to reach Next.js without the sanitizing custom-server.js wrapper trust the client-supplied X-9r-Real-Ip header in src/dashboardGuard.js when isLocalRequest decides whether canAccessPublicLlmApi may skip API-key validation for /api/v1/* routes. A remote unauthenticated attacker can set X-9r-Real-Ip to 127.0.0.1 and be classified as a local client, including on the verified GET /api/v1/models route. This permits unauthorized use of the instance owner's configured LLM providers, consumption of paid credits, and enumeration of configured providers and models. This issue is fixed in version 0.5.6.

EUVD references (3)

Affected products (1)

Vendor	Product	Versions	Platforms
decolua	9router	`< 0.5.6` (affected)	—

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

https://github.com/decolua/9router/security/advisories/GHSA-5mj8-gf6m-fhw8 x_refsource_CONFIRM
https://github.com/decolua/9router/commit/efd20be8d81ef2e256a7037f3aa78e6b567b5fd3 x_refsource_MISC
https://github.com/decolua/9router/releases/tag/v0.5.6 x_refsource_MISC

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (3)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/decolua/9router/commit/efd20be8d81ef2e256a7037f3aa78e6b567b5fd3 security-advisories@github.com
https://github.com/decolua/9router/releases/tag/v0.5.6 security-advisories@github.com
https://github.com/decolua/9router/security/advisories/GHSA-5mj8-gf6m-fhw8 security-advisories@github.com

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-09-23 15:18 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-09-23 15:18 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-23 15:18 UTC
July 18, 2026—Hotpatch KB5121768 (OS Builds 26200.8893 and 26100.8893 ...

web:support.microsoft.com

This out-of-band (OOB) update for Windows 11, version 25H2 and Windows 11, version 24H2 (KB5121768) is cumulative. It includes all improvements from previous security and non-security updates, along with an additional fix . Improvements This OOB update includes the following improvement: [System Performance] This update addresses an issue affecting a limited number of devices with an Intel ...

2026-09-23 15:18 UTC
January 24, 2026—KB5078127 (OS Builds 26200.7628 and 26100.7628) Out-of ...

web:support.microsoft.com

This out-of-band update for Windows 11, version 25H2 and 24H2 (KB5078127) is cumulative. It includes updates from previous security and non-security releases, along with an additional fix . To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information ...

2026-09-23 15:18 UTC
August 2026 CVE Advisory Notification - Security

web:support.servicenow.com

Due to additional analysis provided by the security researcher who discovered CVE - 2026 -6876, we have upgraded the severity rating of CVE - 2026 -6876 from High to Critical. This change affects only the severity

2026-09-23 15:18 UTC
CVE-2026-50656 ShieldBreak Claims Defender Fix Bypass — Megathread

web:windowsforum.com

ShieldBreak, a newly published proof of concept from the researcher known as Nightmare Eclipse, claims to bypass Microsoft's July fix for the Microsoft Defender privilege-escalation flaw CVE - 2026 -50656, better known as RoguePlanet.

2026-09-23 15:18 UTC
Critical Patches Issued for Microsoft Products, August 11, 2026

web:www.cisecurity.org

<p>Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for remote code execution. Successful exploitation of the most severe of these vulnerabilities could result in an attacker gaining the same privileges as the logged-on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or ...

2026-09-23 15:18 UTC
CVE-2026-65681 - High Vulnerability - TheHackerWire

web:www.thehackerwire.com

How do I fix or mitigate CVE - 2026 -65681? To protect against CVE - 2026 -65681, you should: (1) Apply the latest security patches from Microsoft, (2) Check official security advisories for specific remediation steps, (3) Update affected software to the latest version, and (4) Monitor your systems for any signs of exploitation.

2026-09-23 15:18 UTC
Patch Tuesday September 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's September 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-09-23 15:18 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-56681.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "9router",
          "vendor": "decolua",
          "versions": [
            {
              "status": "affected",
              "version": "< 0.5.6"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "9Router is an AI router & token saver. Prior to 0.5.6, 9Router deployments that allow requests to reach Next.js without the sanitizing custom-server.js wrapper trust the client-supplied X-9r-Real-Ip header in src/dashboardGuard.js when isLocalRequest decides whether canAccessPublicLlmApi may skip API-key validation for /api/v1/* routes. A remote unauthenticated attacker can set X-9r-Real-Ip to 127.0.0.1 and be classified as a local client, including on the verified GET /api/v1/models route. This permits unauthorized use of the instance owner's configured LLM providers, consumption of paid credits, and enumeration of configured providers and models. This issue is fixed in version 0.5.6."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-807",
              "description": "CWE-807: Reliance on Untrusted Inputs in a Security Decision",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-22T16:02:25.018Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/decolua/9router/security/advisories/GHSA-5mj8-gf6m-fhw8",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/decolua/9router/security/advisories/GHSA-5mj8-gf6m-fhw8"
        },
        {
          "name": "https://github.com/decolua/9router/commit/efd20be8d81ef2e256a7037f3aa78e6b567b5fd3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/decolua/9router/commit/efd20be8d81ef2e256a7037f3aa78e6b567b5fd3"
        },
        {
          "name": "https://github.com/decolua/9router/releases/tag/v0.5.6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/decolua/9router/releases/tag/v0.5.6"
        }
      ],
      "source": {
        "advisory": "GHSA-5mj8-gf6m-fhw8",
        "discovery": "UNKNOWN"
      },
      "title": "9Router: Authentication Bypass in Public LLM API via Spoofable X-9r-Real-Ip Header"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-56681",
    "datePublished": "2026-09-22T16:02:25.018Z",
    "dateReserved": "2026-06-22T16:39:01.044Z",
    "dateUpdated": "2026-09-22T16:02:25.018Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}