Intel

AIKIDO-2026-906996

better-auth is vulnerable to User Enumeration

User Enumeration Pre-CVE
Found by Aikido Intel before public disclosure or CVE publication.
Published Yesterday

45

Medium Risk

This Affects:

JSbetter-auth
1.3.7 - 1.6.25
Fixed in 1.6.26
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TL;DR

The email OTP plugin exposes a check-verification-otp endpoint that looks up the account by email before validating the submitted one-time code. Because a missing account and a wrong code return different errors, an unauthenticated caller can submit an arbitrary code to learn whether an email is registered. This enables account and email enumeration against the authentication server. The fix validates the OTP first and only reveals account existence after possession of the code is proven.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range and you enable the email OTP plugin.

Background info

better-auth is vulnerable to User Enumeration in versions 1.3.7 - 1.6.25.

How to fix this

Upgrade the better-auth library to the patch version.