HighVulnerabilityLLM-specific

GHSA-86m2-fcxq-5q7c: 9router: Unauthenticated `/v1` proxy access via `Host`-header spoofing → open AI relay + SSRF

Source: GitHub Advisory(opens in a new tab)
Identifiers: CVE-2026-55641GHSA-86m2-fcxq-5q7c
Published: August 28, 2026
Record updated: October 9, 2026

Affected: 9router < 0.5.2
Fixed in: 0.5.2
released June 17, 2026, 72 days before disclosure
Known exploitation: Not listed in the CISA Known Exploited Vulnerabilities catalog at the last check.
EPSS: 0.3%

Summary

9router's request guard treats a request as local, and so exempt from API-key auth on the `/v1` LLM proxy, based on the client-controlled `Host` header in `isLocalRequest` (`src/dashboardGuard.js`). Because the default `DEFAULT_HOST` is `0.0.0.0` and `requireApiKey` is absent from `DEFAULT_SETTINGS`, a remote unauthenticated attacker sending `Host: localhost` gets an open AI relay using the victim's stored API keys, plus unauthenticated SSRF through `/v1/search` via `provider_options.baseUrl` with the `searxng` provider. Affected: 9router <= 0.4.80.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

Details

Scores and exploitation

Patch available: Yes
EPSS: 0.3%Estimated probability that this CVE is exploited in the next 30 days, from the FIRST Exploit Prediction Scoring System. Read on November 3, 2026.
Disclosure date: August 28, 2026

Weaknesses and techniques

AI threat technique (MITRE ATLAS): AML.T0010

Affected

Packages: 9router@< 0.5.2 (fixed: 0.5.2)

Classification

Attack type: Other,
Supply chain
Attack sophistication: Trivial
AI component targeted: API
Impact: Confidentiality,
Integrity,
Availability
Labels: security

How this record was produced

Summaries, mitigations and labels on this page are generated automatically from the source. The linked source is authoritative.

Original source: https://github.com/advisories/GHSA-86m2-fcxq-5q7c

First tracked: August 28, 2026 at 08:01 PM ET, from GitHub Advisory Database

Classifier: claude-haiku-5-5, prompt v4

Classifier confidence: 90% (self-assessed)

Summary

Mitigation

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