9.1Critical
CVE-2026-55196
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.
What this means for your business
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.6% chance of attack attempts being seen in the next 30 days, ranking above 46% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
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Scoring
- CVSS
- 9.1 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N- CVSS v4
- 9.1
- Weakness
- CWE-306
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-06-17
- Last modified
- 2026-09-17
- Sources
- NVD
References
- https://github.com/nesquena/hermes-webui/commit/4d90577e25d5537cb07290eca3fb8abff3bab316
- https://github.com/nesquena/hermes-webui/pull/4171
- https://github.com/nesquena/hermes-webui/pull/4267
- https://github.com/nesquena/hermes-webui/releases/tag/v0.51.442
- https://www.vulncheck.com/advisories/hermes-webui-unauthenticated-passkey-registration-via-authentication-bypass