CVEvulnerability

CVE-2026-53512

9.1 CRITICAL Published 2026-07-15 Modified 2026-07-21 Official page ↗
Status
Analyzed
Published
2026-07-15
Last modified
2026-07-21
Assigner
[email protected]
CVSS 4.0 ([email protected])
9.1 CRITICAL — 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weaknesses
CWE-287, CWE-306, CWE-345, CWE-863

Description

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 configurations

• better-auth better auth (< 1.6.11)

Related

Weakness · CWE (4)

  • CWE-287 Improper Authentication weakness
  • CWE-306 Missing Authentication for Critical Functionality weakness
  • CWE-345 Insufficient Verification of Data Authenticity weakness
  • CWE-863 Incorrect Authorization weakness

References