CVE-2026-55196

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 v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0058

Probability of exploitation

0.43%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-306 Missing Authentication

References

Other 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

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2026-55196? +

CVE-2026-55196 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0058, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-55196? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-6369

An improper access control vulnerability in the canonical-livepatch snap client prior to version 10.15.0 allows a local unprivileged user to …

CVE-2026-9152

A missing authentication vulnerability exists in the Altium 365 SearchService. A legacy SOAP endpoint exposes search index operations without requiring …

CVE-2026-5749

Inadequate access control in the registration process in Fullstep V5, which could allow unauthenticated users to obtain a valid JWT …

CVE-2026-6376

A weakness in SpiceJet’s public booking retrieval page permits full passenger booking details to be accessed using only a PNR …

CVE-2024-45483

A Missing Authentication for Critical Function vulnerability in the GRUB configuration used B&R APROL <4.4-01 may allow an unauthenticated physical …

CVE-2024-54013

Penetration Testing engineers at Amazon have identified a security flaw related to request handling in the web server component that …