The Network Analysis Module (NAM) in Cisco Catalyst Series 6000, 6500, and 7600 allows remote attackers to execute arbitrary commands via certain SNMP packets that are spoofed from the NAM's own IP address. Per: http://www.cisco.com/warp/public/707/cisco-sa-20070228-nam.shtml#@ID
"Only Cisco Catalyst systems that have a NAM on them are affected. This vulnerability affects systems that run Internetwork Operating System (IOS) or Catalyst Operating System (CatOS). "