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.
CVE-2026-55196
Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-06-17. the CNA's CVSS baseline 9.1; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.1
- EG Score
- 9.1(medium)
- EG Risk
- 56(Track)EG Risk 56/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity91% × 45%Exploitation1% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 1%
- EPSS %ILE
- 44%
- KEV
- Not listed
Published
June 17, 2026
Last Modified
July 14, 2026
Advisory Details (5)
Auto-updated Jun 17, 2026Hermes WebUI < 0.51.409 - Unauthenticated Passkey Registration via Authentication Bypass | Advisories | VulnCheck
https://www.vulncheck.com/advisories/hermes-webui-unauthenticated-passkey-registration-via-authentication-bypassv0.51.442
Patch available: nesquena/hermes-webui v0.51.442
https://github.com/nesquena/hermes-webui/releases/tag/v0.51.442Release PC (v0.51.442): [security] require auth for passkey enrollment (#4171)
Patch available: nesquena/hermes-webui v0.51.451 (PR #4267 merged 2026-06-15)
https://github.com/nesquena/hermes-webui/pull/4267[security] fix(auth): require auth for passkey enrollment
Upstream fix in progress (PR #4171 · nesquena/hermes-webui, state=closed)
https://github.com/nesquena/hermes-webui/pull/4171commit 4d90577e25d5 (nesquena/hermes-webui)
Patch available: nesquena/hermes-webui v0.51.451 (contains commit 4d90577e25d5)
https://github.com/nesquena/hermes-webui/commit/4d90577e25d5537cb07290eca3fb8abff3bab316Vendor Advisories for CVE-2026-55196(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 17× in last 7d / 152× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 228 total refreshes for this CVE.
- 2026-07-28 06:08 UTCGHSA enrichment
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Frequently asked(5)
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Dependency Blast Radius
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