CVE-2026-53517

CVE-2026-53517 affects Better Auth’s oauth-provider (and related memory adapter) prior to version 1.6.11. The POST /oauth2/token refresh_token flow performs a non-atomic read–validate–revoke–mint sequence on the oauthRefreshToken row, allowing concurrent requests with the same parent refresh toke...

CVE-2026-53518 Better Auth OAuth Provider: Race Condition in Authorization Code Exchange Enables Multi-Use Code Redemption

Better Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/token endpoint for the authorizationcode grant redeems a single-use authorization code through a non-atomic find-then-delete sequence, allowing two...

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

Overview @better-auth/oauth-provider is an An oauth provider plugin for Better Auth Affected versions of this package are vulnerable to Time-of-check Time-of-use TOCTOU Race Condition through a race condition in the authorizationcode grant handler. An attacker can obtain multiple valid access,...

NPM: @better-auth/oauth-provider's OAuth authorization-code grant allows concurrent redemption when two token requests race the find-then-delete primitive

NPM: @better-auth/oauth-provider's OAuth authorization-code grant allows concurrent redemption when two token requests race the find-then-delete primitive vulnerability discovered by ? in WordPress Npm better-auth versions 1.6.11...

GHSA-7W99-5WM4-3G79 @better-auth/oauth-provider's OAuth authorization-code grant allows concurrent redemption when two token requests race the find-then-delete primitive

Am I affected? Users are affected if all of the following are true: - Their project depends on @better-auth/oauth-provider at a version = 1.6.0, = 1.4.8-beta.7, 1.6.0, or enables the legacy oidc-provider or mcp plugins from better-auth/plugins. - Their application exposes /api/auth/oauth2/token o...