The Connection handler in Hazelcast and Hazelcast Jet allows a remote unauthenticated attacker to access and manipulate data in the cluster with the identity of another already authenticated connection. The affected Hazelcast versions are through 4.0.6, 4.1.9, 4.2.5, 5.0.3, and 5.1.2. The affected Hazelcast Jet versions are through 4.5.3.

The LDAP authentication method in LdapLoginModule in Hazelcast IMDG Enterprise 4.x before 4.0.3, and Jet Enterprise 4.x through 4.2, doesn't verify properly the password in some system-user-dn scenarios. As a result, users (clients/members) can be authenticated even if they provide invalid passwords.