CVE-2026-67335: Better-Auth

Medium severity, CVSS 5.3. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Better-Auth Better-Auth: before 1.6.2 (fixed in 1.6.2)

Published 2026-08-01. Last modified 2026-09-08.