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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.58%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 9.1 CRITICALCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.58% probability · 47th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-306
- Source
- disclosure@vulncheck.com
EPSS 0.6% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.