CVEvulnerability

CVE-2026-67336

9.4 CRITICAL Published 2026-08-01 Modified 2026-09-08 Official page ↗
Status
Deferred
Published
2026-08-01
Last modified
2026-09-08
Assigner
[email protected]
CVSS 4.0 ([email protected])
9.4 CRITICAL — CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
8.7 HIGH — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weaknesses
CWE-327

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.

Related

Weakness · CWE (1)

  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm weakness

References