CVE-2026-41427 HIGH

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

Vendor Better-Auth
Product better-auth
Weakness CWE-863 · Incorrect authorization
Published April 24, 2026
Last update April 27, 2026

CVSS base score

7.1/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 24, 2026 CVE published
April 27, 2026 Record updated