CubeFS is an open-source cloud-native file storage system. A vulnerability was found during in the CubeFS master component in versions prior to 3.3.1 that could allow an untrusted attacker to steal user passwords by carrying out a timing attack. The root case of the vulnerability was that CubeFS used raw string comparison of passwords. The vulnerable part of CubeFS was the UserService of the master component. The UserService gets instantiated when starting the server of the master component. The issue has been patched in v3.3.1. For impacted users, there is no other way to mitigate the issue besides upgrading.