CVE-2026-67335
Received Received - Intake

Authentication Bypass in Better-Auth via Forged OAuth State

Publication date: 2026-08-01

Last updated on: 2026-08-01

Assigner: VulnCheck

Description
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 authorization code to create authenticated sessions bound to the attacker's external identity or persistently link attacker accounts to victim profiles.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-08-01
Last Modified
2026-08-01
Generated
2026-08-01
AI Q&A
2026-08-01
EPSS Evaluated
N/A
NVD
CVE-2026-67335
EUVD
EUVD-2026-51852

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
better-auth better-auth to 1.6.2 (exc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-287 When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

better-auth versions before 1.6.2 do not properly validate the OAuth state parameter when using cookie-backed state storage without PKCE. This allows attackers to forge the state parameter and provide a malicious authorization code, leading to unauthorized session creation or account linking.

Impact Analysis

Attackers could hijack your authenticated sessions or link their accounts to your profiles without consent. This may grant unauthorized access to your data or allow attackers to impersonate you in connected services.

Compliance Impact

This vulnerability could lead to unauthorized data access or account takeover, violating GDPR's data protection principles and HIPAA's security requirements for safeguarding sensitive information.

Mitigation Strategies

Upgrade better-auth to version 1.6.2 or later to address the OAuth state parameter validation issue.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-67335. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart