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Vulnerability record · CVE-2026-55641 · published 10 July 2026

CVE-2026-55641: Authentication bypass by spoofing vulnerability

9Router is an AI router & token saver. Prior to 0.5.2, 9router determines whether a /v1 LLM proxy request is local by reading the client-controlled Host header, allowing a remote unauthenticated attacker to send Host: localhost and bypass API-key authentication. In the default configuration, this exposes the /v1 proxy to upstream provider calls using stored provider credentials and allows /v1/search with the searxng provider_options.baseUrl parameter to drive server-side requests to internal or cloud-metadata hosts. This issue is fixed in version 0.5.2.

8.2 CVSS 3.1 High EPSS 0.32% · top 77.2% CWE-290 · Authentication bypass by spoofingCWE-348 · CWE-348 Deferred
8.2CVSS 3.1 base score
0.32%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
4References
10 Jul 2026Last modified by NVD

Description

9Router is an AI router & token saver. Prior to 0.5.2, 9router determines whether a /v1 LLM proxy request is local by reading the client-controlled Host header, allowing a remote unauthenticated attacker to send Host: localhost and bypass API-key authentication. In the default configuration, this exposes the /v1 proxy to upstream provider calls using stored provider credentials and allows /v1/search with the searxng provider_options.baseUrl parameter to drive server-side requests to internal or cloud-metadata hosts. This issue is fixed in version 0.5.2.

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

References

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

Source: NIST National Vulnerability Database (record CVE-2026-55641), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.