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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-56681
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-22 16:17:48 UTC
Updated2026-09-28 20:17:10 UTC
Description9Router 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.

Risk And Classification

Primary CVSS: v3.1 7.3 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS: 0.009680000 probability, percentile 0.603440000 (date 2026-09-29)

Problem Types: CWE-807 | CWE-807 CWE-807: Reliance on Untrusted Inputs in a Security Decision

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
3.1CNADECLARED7.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Decolua 9router affected < 0.5.6 Not specified

References

ReferenceSourceLinkTags
github.com/decolua/9router/releases/tag/v0.5.6 [email protected] github.com
github.com/decolua/9router/commit/efd20be8d81ef2e256a7037f3aa78e6b567b5fd3 [email protected] github.com
github.com/decolua/9router/security/advisories/GHSA-5mj8-gf6m-fhw8 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
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