High severity8.7NVD Advisory· Published Aug 1, 2026· Updated Sep 8, 2026
CVE-2026-67336
CVE-2026-67336
Description
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 unsigned tokens or intercept authorization codes when PKCE plain is used instead of the required S256 method.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
1- Range: <1.6.11
Patches
Vulnerability mechanics
References
2News mentions
1- Better Auth: 17 Vulnerabilities Disclosed Together, Including Critical Authorization Bypass FlawsVypr Intelligence · Aug 2, 2026