Cisco IOS XR 3.8.3, 3.8.4, and 3.9.1 allows remote attackers to cause a denial of service (NetIO process restart or device reload) via a crafted IPv4 packet, aka Bug ID CSCth44147.
The NETIO and IPV4IO processes in Cisco IOS XR 3.8 through 4.1, as used in Cisco Carrier Routing System and other products, allow remote attackers to cause a denial of service (CPU consumption) via crafted network traffic, aka Bug ID CSCti59888.
Cisco IOS XR 3.9.x and 4.0.x before 4.0.3 and 4.1.x before 4.1.1, when an SPA interface processor is installed, allows remote attackers to cause a denial of service (device reload) via a crafted IPv4 packet, aka Bug ID CSCto45095.
The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS XE 2.1 through 3.17S, IOS XR 2.0.0 through 5.3.2, and NX-OS allows remote attackers to cause a denial of service (packet-processing outage) via crafted ND messages, aka Bug ID CSCuz66542, as exploited in the wild in May 2016.
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.