CVE-2026-67328: @better-auth/sso before 1.6.21 Account Takeover via SSO
@better-auth/sso versions before 1.6.21 contain multiple authentication bypass vulnerabilities in SSO provider handling that allow attackers to sign in as arbitrary users. Attackers can exploit domain verification parsing mismatches, orphaned provider accounts, unbound SAML assertions, or reflected XSS on logout endpoints to gain unauthorized session access and account takeover.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
@better-auth/ssoto a version that resolves this vulnerability.Fixed in 1.6.21 - Compensating control
Until upgraded, restrict access to SSO provider/logout endpoints to trusted clients and monitor/limit requests to reduce the risk of authentication bypass (domain verification parsing mismatches, orphaned provider accounts, unbound SAML assertions) and reflected XSS on logout endpoints.