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THREAT OPS › Threat News › [GHSA] GHSA-86m2-fcxq-5q7c (high) — 9router: Unauthenticated `/v1` proxy access via `Host`-header spoofing → open AI relay + SSRF

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

highgithub_advisoriesPublished 2026-08-28

GHSA-86m2-fcxq-5q7c Severity: high CVE: CVE-2026-55641

9router: Unauthenticated `/v1` proxy access via `Host`-header spoofing → open AI relay + SSRF

## Summary

9router's request guard decides a request is "local" (and therefore exempt from API-key auth on the `/v1` LLM proxy) by reading the **client-controlled `Host` header**. Because 9router binds `0.0.0.0` by default (and the CLI misleadingly

MITRE ATT&CK techniques

CredentialsT1589.001

Indicators of compromise

CVE-2026-55641cve
http://127.0.0.1:url
http://127.0.0.1:19099url
http://VICTIM_IP:20128/v1/messagesurl
http://VICTIM_IP:20128/v1/searchurl
http://169.254.169.254/latest/meta-dataurl
127.0.0.0/8cidr

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