← Vulnerability feed

Vulnerability record · CVE-2026-53512 · published 15 July 2026

CVE-2026-53512: Better-auth better auth improper authentication vulnerability

Better Auth · Better Auth

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.

9.1 CVSS 4.0 Critical EPSS 0.27% · top 82.1% CWE-287 · Improper authenticationCWE-306 · Missing authentication for critical function
9.1CVSS 4.0 base score
0.27%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
21 Jul 2026Last modified by NVD

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.

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:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/better-auth/better-auth/commit/1f2ff4215c4affff0b140b0c0a712c0dde35659c Patch
https://github.com/better-auth/better-auth/pull/9576 Issue TrackingPatch
https://github.com/better-auth/better-auth/releases/tag/v1.6.11 Release Notes
https://github.com/better-auth/better-auth/security/advisories/GHSA-pw9m-5jxm-xr6h MitigationVendor Advisory

Track CVE-2026-53512 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.6CVE-2026-53513Better-auth\/sso improper input validation vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the @better-auth/sso plugin's POST /sso/register and POST…EPSS 0.25%8.3CVE-2026-53516Better-auth better auth improper authentication vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, Better Auth's OAuth callback auto-link gate in handleOAut…EPSS 0.29%8.1CVE-2026-53517Better-auth\/oauth-provider race condition vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. From 1.4.8-beta.7 until 1.6.11, the @better-auth/oauth-provider POST /oaut…EPSS 0.42%7.9CVE-2024-56734Better-auth better auth open redirect vulnerabilityBetter Auth is an authentication library for TypeScript. An open redirect vulnerability has been identified in the verify email endpoint of all versi…EPSS 0.40%7.7CVE-2026-53514Better-auth better auth improper authentication vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, and in 1.6.14 and later when invitation IDs can be obtain…EPSS 0.20%7.6CVE-2026-53518Better-auth\/oauth-provider race condition vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/toke…EPSS 0.41%7.6CVE-2026-45337Better-auth better auth improper authorization vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the deviceAuthorization plugin treats any authent…EPSS 0.21%7.1CVE-2026-53515Better-auth\/sso improper privilege management vulnerabilityBetter Auth is an authentication and authorization library for TypeScript. From 1.2.10 until 1.6.11, the @better-auth/sso plugin's POST /sso/register…EPSS 0.43%

Source: NIST National Vulnerability Database (record CVE-2026-53512), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.