---
id: CVE-2026-55196
title: >-
  Hermes WebUI before 0.51.409 contains an authentication bypass vulnerability
  in passkey registration endpoints that allows unauthenticated remote attackers
  to register arbitrary passkeys
summary: >-
  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
  ex…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-306
vendor: hermes-webui
product: hermes-webui
affected:
  - hermes-webui < 0.51.409
published: '2026-06-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T18:16:48.030'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55196'
references:
  - url: >-
      https://github.com/nesquena/hermes-webui/commit/4d90577e25d5537cb07290eca3fb8abff3bab316
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nesquena/hermes-webui/pull/4171'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nesquena/hermes-webui/pull/4267'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nesquena/hermes-webui/releases/tag/v0.51.442'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/hermes-webui-unauthenticated-passkey-registration-via-authentication-bypass
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-06-23T02:02:11.438761Z'
epss: 0.00817
epssPercentile: 0.55252
ingestedAt: '2026-09-17T18:25:15.969Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.