CVE-2026-53515

Name of the Vulnerable Software and Affected Versions Better Auth versions 1.2.10 through 1.6.10

Description The @better-auth/sso plugin contains a flaw where the registerSSOProvider() function in the 'POST /sso/register' endpoint only verifies organization membership without requiring an owner or admin role. This allows any organization member to attach an attacker-controlled OIDC (OpenID Connect, an identity layer on top of the OAuth 2.0 protocol) or SAML (Security Assertion Markup Language, an XML-based standard for exchanging authentication data) provider to drive organization provisioning via the '/sso/callback/{providerId}' endpoint.

Recommendations Update to version 1.6.11.