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High severity · published Aug 1, 2026
CVE-2026-67328
@better-auth/sso before 1.6.21 Account Takeover via SSO
8.1
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SS
sso · better-auth
before 1.6.21; 1.7.0-beta.0 before 1.7.0-beta.10 · source: vendor
Affected product
SS
sso
better-auth
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-67328
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-67328
vendor-advisory
https://github.com/better-auth/better-auth/security/advisories/GHSA-prpr-5gj3-qqhg
third-party-advisory
https://www.vulncheck.com/advisories/better-auth-sso-before-account-takeover-via-sso
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