Medium severity · published Aug 1, 2026
CVE-2026-67335
better-auth before 1.6.2 OAuth State Validation Bypass
5.3
CVSS
0.3%
EPSS
No
On KEV
Description
better-auth versions before 1.6.2 fail to validate the OAuth state parameter against the stored nonce when using cookie-backed state storage without PKCE. Attackers can forge the state parameter and supply an attacker-controlled authorization code to create authenticated sessions bound to the attacker's external identity or persistently link attacker accounts to victim profiles.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BE
better-auth · better-auth
before 1.6.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-67335
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-67335
github.com
https://github.com/better-auth/better-auth/security/advisories/GHSA-wxw3-q3m9-c3jr
www.vulncheck.com
https://www.vulncheck.com/advisories/better-auth-before-oauth-state-validation-bypass
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