← CVE Radar
CVE-2026-53512Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins
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.
9.1 CRITICALEPSS 0.27%Not in KEVNVD: Analyzed
Overview
Severity
| Score | Severity | Version | Vector String |
|---|---|---|---|
| 9.1 | CRITICAL | 4.0GitHub_M (CNA) | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| 9.1 | CRITICAL | 3.1NVD | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
Details
- CVE ID
- CVE-2026-53512
- Status
- Analyzed
- Assigner (CNA)
- GitHub_M
- Published
- Jul 15, 2026
- Last modified
- 2026-07-21 13:33 UTC
Affected Products
As published by the CNA in the CVE record.
better-authbetter-auth1 version range
- < 1.6.11
References
- github.com https://github.com/better-auth/better-auth/commit/1f2ff4215c4affff0b140b0c0a712c0dde35659c
- github.com https://github.com/better-auth/better-auth/pull/9576
- github.com https://github.com/better-auth/better-auth/releases/tag/v1.6.11
- github.com https://github.com/better-auth/better-auth/security/advisories/GHSA-pw9m-5jxm-xr6h