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CVE-2026-53512

CRITICAL
9.1
CVSS 4.0
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.

Metadata

CVE ID
CVE-2026-53512
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-06-09 17:30 UTC
Published
2026-07-15 17:18 UTC
Last updated
2026-07-15 17:18 UTC
Primary CWE
CWE-287
CWE-287: Improper Authentication
Vendor / Product
better-auth / better-auth
Sources
cve.org  ·  NVD

Severity & Metrics

9.1 CRITICAL CVSS 4.0
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
Affected products (1)
VendorProductPlatformVersions
better-auth better-auth — < 1.6.11
Weakness (CWE)
CWESourceDescription
CWE-287 cna CWE-287: Improper Authentication
CWE-306 cna CWE-306: Missing Authentication for Critical Function
CWE-345 cna CWE-345: Insufficient Verification of Data Authenticity
CWE-863 cna CWE-863: Incorrect Authorization
CVSS scores (1)
ScoreSeverityVersionSourceVector
9.1 CRITICAL 4.0 cna 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
References (4)
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