HIGH

CVE-2026-67336

2026-08-01 CVSS v3.1

CVSS

8.7

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.

Weakness (CWE)

CWE-327

EPSS Score

0.16%

Probability of exploitation in next 30 days

5.5th percentile

References

https://github.com/better-auth/better-auth/security/advisories/GHSA-9h47-pqcx-hjr4 https://www.vulncheck.com/advisories/better-auth-before-insecure-cryptographic-defaults-via-oidcprovider

View on dbcve.org

Base CVE data derived from NVD (public domain). Enrichment by dbcve.org (CC-BY-4.0). Fetched via API.

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