CVE-2026-67335 better-auth before 1.6.2 OAuth State Validation Bypass

better-auth versions before 1.6.2 fail to validate the OAuth state parameter against the stored nonce when using cookie-backed state storage without PKCE. Attackers can forge the state parameter and supply an attacker-controlled authorization code to create authenticated sessions bound to the...

CVE-2026-67335 better-auth before 1.6.2 OAuth State Validation Bypass

better-auth versions before 1.6.2 fail to validate the OAuth state parameter against the stored nonce when using cookie-backed state storage without PKCE. Attackers can forge the state parameter and supply an attacker-controlled authorization code to create authenticated sessions bound to the...

GHSA-WXW3-Q3M9-C3JR Better Auth: OAuth callback accepts mismatched `state` when cookie-backed state storage is used without PKCE

Am I affected? Users are affected if all of the following are true: - The application uses better-auth at a version below 1.6.2 or @better-auth/sso paired with such a version. - betterAuth account: storeStateStrategy is set to "cookie". The default "database" is not affected. - The application...