Hermes WebUI < 0.51.409 - Unauthenticated Passkey Registration via Authentication Bypass
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-306.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| hermes-webui | hermes-webui | before 0.51.409 | 0.51.409 | Patch available | CNA |
- hermes-webui Vendorhermes-webui Affected before 0.51.409 Fixed in 0.51.409 Patch available CNA
Remediation
- Fix · CNA hermes-webui (hermes-webui) Fixed in 0.51.409
Timeline
- 2026-10-02 Threatist record created from CVE-2026-55196
- 2026-10-03 Alias added: GHSA-5j37-rf54-82q2
- 2026-10-25 EPSS moved to the below the 50th percentile
References
Sources
- CVE-2026-55196 · CVE Program
- CVE-2026-55196 · NVD
- FIRST EPSS
- GHSA-5j37-rf54-82q2 · GitHub Advisory Database · CC BY 4.0
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