It's pretty rare that we discuss security issues for hardware devices that don't have real operating systems, but Hewlett-Packard has published a security bulletin about a security issue with a number of their printers. To quote the bulletin, "A potential security vulnerability has been identified with certain HP LaserJet printers, HP Color LaserJet printers and HP Digital Senders. The vulnerability could be exploited remotely to gain unauthorized access to files."
This affects a number of HP printers, and the security bulletin lists the models affected and the firmware versions necessary to patch the vulnerability. Downloads are not available from that page, so you'll need to click the "Download drivers and software" link and choose your model to get the right driver.