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.
- Score
- CVSS 3.1 8.1 High
- Status
- Analyzed - security-advisories@github.com
- Published
- 2026-07-15
- Last modified
- 2026-07-15
- Weaknesses
- CWE-362, CWE-367
Affected products
- Better-auth (Better-auth)
- Better-auth/oauth-provider (Better-auth)
- Better Auth (Better-auth)
- Oauth-provider (Better-auth)
References
- https://github.com/better-auth/better-auth/commit/c6918ecc9e3a75892169415d7f6c95b591b6a52d
- https://github.com/better-auth/better-auth/releases/tag/v1.6.11
- https://github.com/better-auth/better-auth/security/advisories/GHSA-392p-2q2v-4372
