I am sure many of you have already heard about this, but:

Software bugs in a fundamental language of the Internet could leave routers, switches and even PCs open to attack, an Internet security watchdog said Tuesday.

The problems affect the Simple Network Management Protocol, or SNMP, a basic language used to talk to routers, switches, printers and other managed network devices to allow network engineers to glean status and performance information.
Story at: http://zdnet.com.com/2100-1105-835500.html

CERT advisory at: http://www.cert.org/advisories/CA-2002-03.html