high8.1
CVE-2026-53517
Better Auth: OAuth refresh-token rotation forks the token family on concurrent redemption
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | @better-auth/oauth-provider | >= 1.6.0, < 1.6.11 | 1.6.11 |
| npm | better-auth | >= 1.4.8-beta.7, < 1.6.0 | 1.6.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Better-Auth | Better-Auth\/Oauth-Provider | from 1.6.0 before 1.6.11 |
| Better-Auth | Better Auth | from 1.4.9 before 1.6.11 Version 1.4.8 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-392p-2q2v-4372
- https://github.com/better-auth/better-auth/security/advisories/GHSA-392p-2q2v-4372
- https://github.com/better-auth/better-auth/releases/tag/v1.6.0
- https://github.com/better-auth/better-auth/releases/tag/v1.6.11
- https://nvd.nist.gov/vuln/detail/CVE-2026-53517
- https://github.com/better-auth/better-auth/commit/c6918ecc9e3a75892169415d7f6c95b591b6a52d