Executive brief
KeystoneJS Keystone is a popular Node.js framework for building content management systems and backend APIs. A bug in the default sign-in functionality allows attackers to authenticate using incomplete or partial email addresses, provided they know the correct password. This could enable account takeover if an attacker can guess or brute-force a partial email address combined with a weak password.
Technical details
The vulnerability is an authentication weakness in Keystone's default sign-in logic that performs incomplete email address validation. The bug allows email matching on partial strings rather than exact matches, meaning a user account with email "user@example.com" could be logged into using "user@" or similar incomplete variants. A correct password is still required, so this is not a complete authentication bypass. The issue affects all versions prior to 0.3.16. The attack vector is network-based and requires no special privileges, though the attacker must know or guess both a valid partial email and the correct password.
Affected products
- KeystoneJS keystone before 0.3.16
Timeline
- 2020-08-19: disclosed
- 2019-05-29: patched: Fixed in version 0.3.16