CVE-2026-53512: Better Auth is an authentication and authorization library for TypeScript

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-53512 is a critical-severity flaw (CVSS 9.1) affecting better auth. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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/oauth

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 80%)
CISA exploited list	No
Weakness	CWE-287, CWE-306, CWE-345, CWE-863
Published	2026-07-15
Last modified	2026-07-21

Publisher (CNA): GitHub, Inc. · Vendor: better-auth

Last updated 2026-07-21 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-15 18:16 UTCPublished CVE record published
2026-07-21 13:33 UTCUpdated Record last modified

better-auth better auth UPGRADE

Affected: < 1.6.11

Fixed in: 1.6.11

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls better-auth

2. UPGRADE to 1.6.11

npm install better-auth@">=1.6.11"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-53512?

better auth: upgrade to 1.6.11. Exact commands for each OS are on this page.

Is CVE-2026-53512 being exploited?

CVE-2026-53512 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-53512 affect?

CVE-2026-53512 affects better auth. Severity is critical (CVSS 9.1). 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 refreshTok

How urgent is CVE-2026-53512?

Priority 42/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-53518 HIGH 8.1 UPGRADE UPGRADE Better Auth is an authentication and authorization library for TypeScript
CVE-2026-53517 HIGH 8.1 UPGRADE UPGRADE Better Auth is an authentication and authorization library for TypeScript
CVE-2026-53513 CRITICAL 9.6 UPGRADE UPGRADE Better Auth is an authentication and authorization library for TypeScript
CVE-2026-53515 HIGH 7.1 UPGRADE UPGRADE Better Auth is an authentication and authorization library for TypeScript
CVE-2026-53516 HIGH 8.3 UPGRADE Better Auth is an authentication and authorization library for TypeScript

References

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