CVE-2026-55196 Hermes WebUI < 0.51.409 - Unauthenticated Passkey Registration via Authentication Bypass
Unauthenticated attackers can register passkeys to gain administrative control when passkey support is enabled without existing credentials.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-55196?
CVE-2026-55196 is a critical authentication bypass vulnerability in hermes-webui, published on 17 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-306
Which versions are affected by CVE-2026-55196?
How do I fix CVE-2026-55196?
No fix has been published for CVE-2026-55196 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-55196 being exploited?
There is no known exploitation of CVE-2026-55196 in the wild and no public exploit code.
Sources
Also known as GHSA-5j37-rf54-82q2.