What is CVE-2026-67336?

CVE-2026-67336 is a high-severity vulnerability in Better-auth, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 8.7/10. Published 2026-08-01.

How severe is CVE-2026-67336?

High severity. CVSS v3 base score is 8.7 out of 10.

Vulnerability in Better-auth

CVE-2026-67336

better-auth versions before 1.6.11 contain insecure cryptographic defaults in the oidcProvider and mcp plugins that advertise the none algorithm and accept plain PKCE by default. Attackers can exploit algorithm negotiation to accept unsign…

Vulnerability class: POODLE (CVE-2014-3566)

CVSS v3 metric

CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N.

Affected products

Better-auth — versions 0, 1.6.11

Weakness classification (CWE)

CWE-327 — Use of a Broken or Risky Cryptographic Algorithm

References

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

Frequently asked questions

What is CVE-2026-67336?: CVE-2026-67336 is a high-severity vulnerability in Better-auth, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 8.7/10. Published 2026-08-01.
How severe is CVE-2026-67336?: High severity. CVSS v3 base score is 8.7 out of 10.