Critical 9.1Published Jun 17, 2026

CVE-2026-55196Hermes WebUI < 0.51.409 - Unauthenticated Passkey Registration via Authentication Bypass

Updated under an hour ago (Oct 27, 2026, 2:30 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

Hermes WebUI before 0.51.409 contains an authentication bypass vulnerability in passkey registration endpoints that allows unauthenticated remote attackers to register arbitrary passkeys. When HERMES_WEBUI_PASSKEY=1 is enabled with no existing credentials, POST /api/auth/passkey/register/options and POST /api/auth/passkey/register endpoints are accessible without authentication, allowing attackers to claim the first passkey and gain permanent administrative control.

CVSS: 9.1 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-306
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Sep 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

hermes-webui hermes-webui hermes_webui:hermes_webui (from the name)	before 0.51.409; 0.51.409 not affected	CNA record

References

References

https://github.com/nesquena/hermes-webui/releases/tag/v0.51.442	release-notes
https://github.com/nesquena/hermes-webui/pull/4171	issue-tracking, patch
https://github.com/nesquena/hermes-webui/pull/4267	issue-tracking, patch
https://github.com/nesquena/hermes-webui/commit/4d90577e25d5537cb07290eca3fb8abff3bab316	patch
https://www.vulncheck.com/advisories/hermes-webui-unauthenticated-passkey-registration-via-authentication-bypass	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.