CVE-2026-55196

Critical

Description

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.

SeverityCritical

CVSS9.1

Exploit probability—

ProductHermes-webui

PublishedJun 17, 2026

First seenJun 17, 2026

Weakness typeCWE-306Missing authentication for critical function

How to fix

Update

hermes-webui hermes-webui0.51.409 or later

Patches

Vendor advisories

github.com/nesquena/hermes-webui/releases/tag/v0.51.442

Affected products

Product	Affected versions	Fixed in
hermes-webui hermes-webui	v < 0.51.409	0.51.409

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