b4bc65a007
The `authorization_code` grant's verification step was a `findOne` + `deleteOne` pair, so two concurrent `POST /oauth2/token` requests sharing the same `code` both pass the find, both delete, and both mint independent access/refresh/id token sets: a CAS gap that lets an authorization code be redeemed twice. The legacy `oidc-provider` and `mcp` plugins in `better-auth` share the same primitive on their `authorization_code` paths and have the same gap. All three call sites now use `internalAdapter.consumeVerificationValue` (the atomic primitive added in better-auth#9560 and renamed in better-auth#9568): the first concurrent caller receives the row and mints tokens, subsequent racers receive `null`. The consumed and expired paths return RFC 6749 §5.2 `invalid_grant` instead of the better-auth-internal `invalid_verification`, so spec-compliant clients can branch on the standard code. The redundant second `deleteVerificationByIdentifier` call after PKCE validation in the legacy paths is removed. Closes GHSA-7w99-5wm4-3g79. Co-authored-by: chdanielmueller <4051999+chdanielmueller@users.noreply.github.com>
Better Auth
Better Auth is a framework-agnostic authentication (and authorization) framework for TypeScript. It provides a comprehensive set of features out of the box and includes a plugin ecosystem that simplifies adding advanced functionalities with minimal code in a short amount of time. Whether you need 2FA, multi-tenant support, or other complex features, it lets you focus on building your actual application instead of reinventing the wheel.
Why Better Auth
Authentication in the TypeScript ecosystem is a half-solved problem. Other open-source libraries often require a lot of additional code for anything beyond basic authentication. Rather than just pushing third-party services as the solution, I believe we can do better as a community—hence, Better Auth.
Contribution
Better Auth is a free and open source project licensed under the MIT License. You are free to do whatever you want with it.
You could help continuing its development by:
Security
If you discover a security vulnerability within Better Auth, please send an e-mail to security@better-auth.com.
All reports will be promptly addressed, and you'll be credited accordingly.