A hack in a dream is read as fear of intrusion: your private space, data or thoughts being reached without consent. It also stands for feeling that the systems you rely on are less secure than they seem.
Where in your waking life have you met something like this lately?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.