CVE-2026-53517

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.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

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/c6918ecc9e3a75892169415d7f6c95b591b6a52d	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-392p-2q2v-4372	Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:better-auth:better-auth\/oauth-provider::::::node.js::*
	cpe:2.3:a:better-auth:better_auth::::::node.js::*
	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::*

History

No history.

Information

Published : 2026-07-15 18:16

Updated : 2026-07-21 16:00

NVD link : CVE-2026-53517

Mitre link : CVE-2026-53517

CVE.ORG link : CVE-2026-53517

JSON object : View

Products Affected

better-auth

better-auth\/oauth-provider
better_auth

CWE

CWE-362

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

CWE-367

Time-of-check Time-of-use (TOCTOU) Race Condition

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