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OpenAdvisories
High · 7.3 Scanner template CVE-2026-56681 EUVD-2026-84541GHSA-5mj8-gf6m-fhw8

9Router: Authentication Bypass in Public LLM API via Spoofable X-9r-Real-Ip Header

Published Sep 22, 2026 · Updated Sep 28, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
decolua 9router < 0.5.6 —

Automated scanner template

A ready-made Nuclei template detects this vulnerability automatically. Vulnerabilities with public scanner templates are typically probed across the internet soon after the template appears — exposed systems should be patched first.

Source: projectdiscovery/nuclei-templates (MIT) — updated daily. Only links are listed.

Affected packages

EcosystemPackageAffectedFixedRecord
npm 9router < 0.5.8 0.5.8 GHSA-5mj8-gf6m-fhw8

References