CVE-2026-41427 — Better Auth OAuth 2.1 Provider: Unprivileged users can register OAuth clients

Description (CNA)

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.5, the clientPrivileges option documents a create action, but the OAuth client creation endpoints did not invoke the hook before persisting new clients. Deployments that configured clientPrivileges to restrict client registration were not actually restricted — any authenticated user could reach the create endpoints and register an OAuth client with attacker-chosen redirect URIs and metadata. This vulnerability is fixed in 1.6.5.

Affected (CNA)

Vendor / product	Versions
better-auth / better-auth	affected >= 1.4.8-beta.7, < 1.6.5; affected >= 1.7.0-beta.0, <= 1.7.0-beta.1
better-auth / oauth-provider	affected >= 1.4.8-beta.7, < 1.6.5; affected >= 1.7.0-beta.0, <= 1.7.0-beta.1

CWE

CWE-863

References

https://github.com/better-auth/better-auth/security/advisories/GHSA-xr8f-h2gw-9xh6

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.