What is CVE-2026-67335?

CVE-2026-67335 is a medium-severity vulnerability in Better-auth, classified under Improper Authentication. CVSS score: 5.3/10. Published 2026-08-01.

How severe is CVE-2026-67335?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Auth bypass in Better-auth

CVE-2026-67335

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 authorizat…

Vulnerability class: Broken Authentication

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N.

Affected products

Better-auth — versions 0, 1.6.2

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

disclosure@vulncheck.com (vendor-advisory)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-67335?: CVE-2026-67335 is a medium-severity vulnerability in Better-auth, classified under Improper Authentication. CVSS score: 5.3/10. Published 2026-08-01.
How severe is CVE-2026-67335?: Medium severity. CVSS v3 base score is 5.3 out of 10.