A vulnerability, which was classified as problematic, has been found in Cosmote Greece What's Up App 4.47.3 on Android. This issue affects some unknown processing of the file gr/desquared/kmmsharedmodule/db/RealmDB.java of the component Realm Database Handler. The manipulation of the argument defaultRealmKey leads to use of default cryptographic key. Local access is required to approach this attack. The complexity of an attack is rather high. The exploitation is known to be difficult. The vendor was contacted early about this disclosure but did not respond in any way.