← CVE Intelligence

CVE-2026-53512

Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
better-auth / better-authaffected < 1.6.11

CWE

CWE-287, CWE-306, CWE-345, CWE-863

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.