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.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-67328?
The severity of CVE-2026-67328 is rated as high with a score of 8.6.
How does CVE-2026-67328 allow account takeover?
CVE-2026-67328 allows account takeover via multiple authentication bypass vulnerabilities in SSO provider handling.
Which versions of @better-auth/sso are affected by CVE-2026-67328?
CVE-2026-67328 affects all versions of @better-auth/sso before 1.6.21.
How do I fix CVE-2026-67328?
To fix CVE-2026-67328, upgrade your @better-auth/sso package to version 1.6.21 or later.
What kind of attacks can be executed using CVE-2026-67328?
Attackers can exploit CVE-2026-67328 to sign in as arbitrary users through various vulnerabilities such as domain verification parsing mismatches.