Enumeration of valid usernames in web-auth/webauthn-lib
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-204.
Summary
web-auth/webauthn-lib is an open source set of PHP libraries and a Symfony bundle to allow developers to integrate that authentication mechanism into their web applications. The ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found. When WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames. By knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks. This issue has been addressed in version 4.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
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 |
|---|---|---|---|---|---|
| web-auth | webauthn-framework | 4.5.0 to before 4.9.0 | 4.9.0 | Patch available | CNA |
| — | web-auth/webauthn-lib (Packagist) | 4.5.0 to before 4.9.0 | 4.9.0 | Patch available | GHSA-875x-g8p7-5w27 |
| — | web-auth/webauthn-framework (Packagist) | 4.5.0 to before 4.9.0 | 4.9.0 | Patch available | GHSA-875x-g8p7-5w27 |
- webauthn-framework Vendorweb-auth Affected 4.5.0 to before 4.9.0 Fixed in 4.9.0 Patch available CNA
- web-auth/webauthn-lib (Packagist) Vendor— Affected 4.5.0 to before 4.9.0 Fixed in 4.9.0 Patch available GHSA-875x-g8p7-5w27
- web-auth/webauthn-framework (Packagist) Vendor— Affected 4.5.0 to before 4.9.0 Fixed in 4.9.0 Patch available GHSA-875x-g8p7-5w27
CPE names CISA-ADP · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:spomky-labs:webauthn_framwork:4.5.0:*:*:*:*:*:*:* | 4.5.0 | — | Spomky-labs |
- cpe:2.3:a:spomky-labs:webauthn_framwork:4.5.0:*:*:*:*:*:*:* Versions 4.5.0 — ·Spomky-labs
Remediation
- Fix · CNA webauthn-framework (web-auth) Fixed in 4.9.0
- Fix · GHSA-875x-g8p7-5w27 web-auth/webauthn-lib (Packagist) Fixed in 4.9.0 Advisory →
- Fix · GHSA-875x-g8p7-5w27 web-auth/webauthn-framework (Packagist) Fixed in 4.9.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2024-39912
- 2026-10-03 Alias added: GHSA-875x-g8p7-5w27
References
Other 5
- https://github.com/web-auth/webauthn-framework/security/advisories/GHSA-875x-g8p7-5w27
- https://github.com/web-auth/webauthn-framework/commit/64de11f6cddc71e56c76e0cc4573bf94d02be045
- https://github.com/web-auth/webauthn-framework/commit/a9d1352897fba552e659e1445a771dec2d4ed05a
- https://github.com/web-auth/webauthn-lib/commit/b6798de27cdedd8681fe4c9b13ace0ff2456d18b
- https://github.com/web-auth/webauthn-framework
Sources
- CVE-2024-39912 · CVE Program
- CVE-2024-39912 · NVD
- FIRST EPSS
- GHSA-875x-g8p7-5w27 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences