CVE-2026-53512

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the legacy oidcProvider and mcp plugins expose OAuth token endpoints whose refresh_token grant authenticates only possession of the bound refreshToken row and matching client_id, without verifying the confidential client's client_secret, allowing an attacker with a valid refresh_token to mint access tokens and rotated refresh tokens through /api/auth/oauth2/token or /api/auth/mcp/token. The @better-auth/oauth-provider package is not affected. This issue is fixed in version 1.6.11.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/better-auth/better-auth/commit/1f2ff4215c4affff0b140b0c0a712c0dde35659c	Patch
https://github.com/better-auth/better-auth/pull/9576	Issue Tracking Patch
https://github.com/better-auth/better-auth/releases/tag/v1.6.11	Release Notes
https://github.com/better-auth/better-auth/security/advisories/GHSA-pw9m-5jxm-xr6h	Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-07-15 18:16

Updated : 2026-07-21 13:33

NVD link : CVE-2026-53512

Mitre link : CVE-2026-53512

CVE.ORG link : CVE-2026-53512

JSON object : View

Products Affected

better-auth

better_auth

CWE

CWE-287

Improper Authentication

CWE-306

Missing Authentication for Critical Function

CWE-345

Insufficient Verification of Data Authenticity

CWE-863

Incorrect Authorization

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