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CVE-2026-53518

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

Description (CNA)

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 authorization_code grant redeems a single-use authorization code through a non-atomic find-then-delete sequence, allowing two concurrent requests to pass the read step and mint independent access tokens, refresh tokens, and ID tokens; legacy /oauth2/token and /mcp/token paths in oidc-provider and mcp plugins share the same primitive. This issue is fixed in version 1.6.11.

Affected (CNA)

Vendor / productVersions
better-auth / better-authaffected >= 1.6.0, < 1.6.11

CWE

CWE-362, CWE-367

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.