According to a CERT vulnerability note, Samsung's networked printers along with certain Dell printers manufactured by Samsung "contain a hardcoded account that could allow a remote attacker to take control of an affected device."
This is not good.
Even if SNMP is disabled, this "backdoor administrator account" is still active and could be used by an attacker to access the printer.
From there, he or she may be able to change the printer's configuration, access information including credentials and information sent to the printer, and potentially run undesirable code in the printer.
In the meantime, a partial defence might be to block SNMP traffic at the firewall, but that would not stop an inside attack.
A list of models affected by this vulnerability was not provided, so until those details are provided the cautious approach would be to assume it applies to all network-capable printers with SNMP support that were released by Samsung or Dell prior to this month.