Cisco IOS on Catalyst 3750X switches has default Service Module credentials, which makes it easier for local users to gain privileges via a Service Module login, aka Bug ID CSCue92286.
The remember feature in the DHCP server in Cisco IOS allows remote attackers to cause a denial of service (device reload) by acquiring a lease and then sending a DHCPRELEASE message, aka Bug ID CSCuh46822.
The OSPF functionality in Cisco IOS and IOS XE allows remote attackers to cause a denial of service (device reload) via crafted options in an LSA type 11 packet, aka Bug ID CSCui21030.
The NTP implementation in Cisco IOS 12.0 through 12.4 and 15.0 through 15.1, and IOS XE 2.1 through 3.3, does not properly handle encapsulation of multicast NTP packets within MSDP SA messages, which allows remote attackers to cause a denial of service (device reload) by leveraging an MSDP peer relationship, aka Bug ID CSCuc81226.
Memory leak in Cisco IOS 12.2, 15.1, and 15.2; IOS XE 3.4.2S through 3.4.5S; and IOS XE 3.6.xS before 3.6.1S allows remote attackers to cause a denial of service (memory consumption or device reload) via malformed IKEv1 packets, aka Bug ID CSCtx66011.
Race condition in the IPv6 virtual fragmentation reassembly (VFR) implementation in Cisco IOS 12.2 through 12.4 and 15.0 through 15.3 allows remote attackers to cause a denial of service (device reload or hang) via fragmented IPv6 packets, aka Bug ID CSCud64812.
Cisco IOS 12.2 through 12.4 and 15.0 through 15.3, and IOS XE 2.1 through 3.9, allows remote attackers to cause a denial of service (device reload) via crafted DHCP packets that are processed locally by a (1) server or (2) relay agent, aka Bug ID CSCug31561.
The Zone-Based Firewall (ZFW) feature in Cisco IOS 15.1 through 15.2, when content filtering or HTTP ALG inspection is enabled, allows remote attackers to cause a denial of service (device reload or hang) via crafted IPv4 HTTP traffic, aka Bug ID CSCtx56174.
The T1/E1 driver-queue functionality in Cisco IOS 12.2 and 15.0 through 15.3, when an HDLC32 driver is used, allows remote attackers to cause a denial of service (interface queue wedge) via bursty network traffic, aka Bug ID CSCub67465.
Cisco IOS 15.0 through 15.3 and IOS XE 3.2 through 3.8, when a VRF interface exists, allows remote attackers to cause a denial of service (interface queue wedge) via crafted UDP RSVP packets, aka Bug ID CSCuf17023.