CVE-2026-67328 PUBLISHED

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

Assigner: VulnCheck
Reserved: 29.07.2026 Published: 01.08.2026 Updated: 01.08.2026

@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.

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS Score: 8.6

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	Low
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CVSS Score: 8.1

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	better-auth
Product	sso
Versions	Default: unaffected affected from 0 to 1.6.21 (excl.) Version 1.6.21 is unaffected

Vendor	better-auth
Product	sso
Versions	Default: unaffected affected from 1.7.0-beta.0 to 1.7.0-beta.10 (excl.) Version 1.7.0-beta.10 is unaffected

References

Problem Types

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE