Preview Junk Mail

No you cannot be hacked by just opening and viewing a junk email message.

However, if it contains links and/or attachments, AND you click on any of the links and/or attachments, you can be hacked.

As previously outlined - not Hacked but if clicking on Links within the Junk Mail can be presented with possible Malware / Adware.

Effective defenses against malware and other threats

No, you can’t be hacked by clicking on a link in an email.