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OpenAdvisories
High · 8.1 CVE-2026-67328 EUVD-2026-51839GHSA-8g2f-78cq-p655

@better-auth/sso before 1.6.21 Account Takeover via SSO

Published Aug 1, 2026 · Updated Oct 8, 2026 · Assigned by VulnCheck

Description

@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 products

VendorProductAffectedFixed
better-auth sso < 1.6.21, 1.7.0-beta.0 – < 1.7.0-beta.10 1.6.21

References