Auth bypass in Better-Auth
CVE-2026-41427
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.
Vulnerability class: Broken Access Control
EPSS: 0.002 (11.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Better-auth — versions >= 1.4.8-beta.7, < 1.6.5, >= 1.7.0-beta.0, <= 1.7.0-beta.1
- Better-auth Better-auth\/oauth-provider — versions 1.4.8, 1.7.0
- Better-auth Oauth-provider — versions >= 1.4.8-beta.7, < 1.6.5, >= 1.7.0-beta.0, <= 1.7.0-beta.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-41427?
- CVE-2026-41427 is a medium-severity vulnerability in Better-Auth, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-04-24.
- How severe is CVE-2026-41427?
- Medium severity. CVSS v3 base score is 6.5 out of 10.