CVE-2026-53516

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, Better Auth's OAuth callback auto-link gate in handleOAuthUserInfo accepts implicit account linking when the OAuth provider asserts email_verified: true without requiring the local user row's emailVerified field to also be true, allowing an attacker who pre-registers a victim email through /sign-up/email to bind the victim's OAuth identity to the attacker's account. The same primitive affects one-tap, and emailAndPassword.requireEmailVerification: true does not mitigate the link-time verification change. This issue is fixed in version 1.6.11.

• github.comhttps://github.com/better-auth/better-auth/commit/da7e50beee849c59a2ed1ec6b3a38cc6ab9fb563
• github.comhttps://github.com/better-auth/better-auth/pull/9578
• github.comhttps://github.com/better-auth/better-auth/releases/tag/v1.6.11
• github.comhttps://github.com/better-auth/better-auth/security/advisories/GHSA-g38m-r43w-p2q7