Cisco IOS XR through 5.3.2 mishandles Local Packet Transport Services (LPTS) flow-base entries, which allows remote attackers to cause a denial of service (session drop) by making many connection attempts to open TCP ports, aka Bug ID CSCux95576.
http://www.securitytracker.com/id/1035934
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160519-ios-xr