CVE-2026-67335

Description

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 attacker's external identity or persistently link attacker accounts to victim profiles.

References

• https://github.com/better-auth/better-auth/security/advisories/GHSA-wxw3-q3m9-c3jr
• https://www.vulncheck.com/advisories/better-auth-before-oauth-state-validation-bypass