Cisco IOS 12.2 and 15.0 through 15.3 allows remote attackers to cause a denial of service (traffic-processing outage) via a crafted series of Common Industrial Protocol (CIP) requests, aka Bug ID CSCur69036.
http://www.securitytracker.com/id/1036914
http://www.securityfocus.com/bid/93197
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160928-cip