CVE-2026-53517

Severity CVSS v4.0:

Pending analysis

Type:

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Publication date:

15/07/2026

Last modified:

21/07/2026

Description

Better Auth is an authentication and authorization library for TypeScript. From 1.4.8-beta.7 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/token endpoint on the refresh_token grant performs a non-atomic read, validate, revoke, and mint sequence on the oauthRefreshToken row, allowing concurrent requests with the same parent refresh token to pass the revoked check and create forked refresh-token families; the vulnerable range also includes embedded better-auth plugin versions before 1.6.0. This issue is fixed in version 1.6.11.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N CVSS v3.1 Severity and Metrics:

Base Score: 8.10 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): None

Base Score 3.x

8.10

Severity 3.x

HIGH

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:better-auth:better-auth\/oauth-provider::::::node.js::*	1.6.0 (including)	1.6.11 (excluding)
cpe:2.3:a:better-auth:better_auth::::::node.js::*	1.4.9 (including)	1.6.11 (excluding)
cpe:2.3:a:better-auth:better_auth:1.4.8:-::::node.js::*
cpe:2.3:a:better-auth:better_auth:1.4.8:beta7::::node.js::*

To consult the complete list of CPE names with products and versions, see this page

CVE-2026-53517

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools