The Zone-Based Firewall (ZBFW) functionality in Cisco IOS, possibly 15.4 and earlier, and IOS XE, possibly 3.13 and earlier, mishandles zone checking for existing sessions, which allows remote attackers to bypass intended resource-access restrictions via spoofed traffic that matches one of these sessions, aka Bug IDs CSCun94946 and CSCun96847.

The server IKEv1 implementation in Cisco IOS 12.2 through 12.4 and 15.0 through 15.6, IOS XE through 3.18S, IOS XR 4.3.x and 5.0.x through 5.2.x, and PIX before 7.0 allows remote attackers to obtain sensitive information from device memory via a Security Association (SA) negotiation request, aka Bug IDs CSCvb29204 and CSCvb36055 or BENIGNCERTAIN.

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 XE before 3.1.2S on ASR 1000 devices mishandles the automatic setup of Virtual Fragment Reassembly (VFR) by certain firewall and NAT components, which allows remote attackers to cause a denial of service (Embedded Services Processor crash) via crafted IP packets, aka Bug IDs CSCtf87624, CSCte93229, CSCtd19103, and CSCti63623.

Cisco IOS XE before 3.7.5S on ASR 1000 devices does not properly handle route adjacencies, which allows remote attackers to cause a denial of service (device hang) via crafted IP packets, aka Bug ID CSCub31873.

Cisco IOS XE 3.5E and earlier on WS-C3850, WS-C3860, and AIR-CT5760 devices does not properly parse the "request system shell" challenge response, which allows local users to obtain Linux root access by leveraging administrative privilege, aka Bug ID CSCur09815.

The Ethernet Connectivity Fault Management (CFM) handling feature in Cisco IOS 12.2(33)SRE9a and earlier and IOS XE 3.13S and earlier allows remote attackers to cause a denial of service (device reload) via malformed CFM packets, aka Bug ID CSCuq93406.

Cisco IOS 12.4 and 15.0 through 15.4 and IOS XE 3.1.xS, 3.2.xS, 3.3.xS, 3.4.xS, 3.5.xS, 3.6.xS, and 3.7.xS before 3.7.6S; 3.8.xS, 3.9.xS, and 3.10.xS before 3.10.1S; and 3.11.xS before 3.12S allow remote attackers to cause a denial of service (device reload) via a crafted SIP message, aka Bug ID CSCul46586.

Cisco IOS 12.0, 12.2, 12.4, 15.0, 15.1, 15.2, and 15.3 and IOS XE 2.x and 3.x before 3.7.4S; 3.2.xSE and 3.3.xSE before 3.3.2SE; 3.3.xSG and 3.4.xSG before 3.4.4SG; and 3.8.xS, 3.9.xS, and 3.10.xS before 3.10.1S allow remote attackers to cause a denial of service (device reload) via malformed RSVP packets, aka Bug ID CSCui11547.

The L2TP module in Cisco IOS XE 3.10S(.2) and earlier on ASR 1000 routers allows remote authenticated users to cause a denial of service (ESP card reload) via a malformed L2TP packet, aka Bug ID CSCun09973.

Cisco ASR 1000 devices with software before 3.8S, when BDI routing is enabled, allow remote attackers to cause a denial of service (device reload) via crafted (1) broadcast or (2) multicast ICMP packets with fragmentation, aka Bug ID CSCub55948.

Cisco IOS XE 3.7S(.1) and earlier allows remote attackers to cause a denial of service (Packet Processor crash) via fragmented MPLS IP packets, aka Bug ID CSCul00709.

Cisco IOS XE 3.8S(.2) and earlier does not properly use a DHCP pool during assignment of an IP address, which allows remote authenticated users to cause a denial of service (device reload) via an AAA packet that triggers an address requirement, aka Bug ID CSCuh04949.

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 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.

The OSPF implementation in Cisco IOS 12.0 through 12.4 and 15.0 through 15.3, IOS-XE 2.x through 3.9.xS, ASA and PIX 7.x through 9.1, FWSM, NX-OS, and StarOS before 14.0.50488 does not properly validate Link State Advertisement (LSA) type 1 packets before performing operations on the LSA database, which allows remote attackers to cause a denial of service (routing disruption) or obtain sensitive packet information via a (1) unicast or (2) multicast packet, aka Bug IDs CSCug34485, CSCug34469, CSCug39762, CSCug63304, and CSCug39795.

Cisco IOS XE 2.x and 3.x before 3.4.5S, and 3.5 through 3.7 before 3.7.1S, on 1000 series Aggregation Services Routers (ASR) allows remote attackers to cause a denial of service (card reload) by sending many crafted L2TP packets, aka Bug ID CSCtz23293.

The General Responder implementation in the IP Service Level Agreement (SLA) feature in Cisco IOS 15.2 and IOS XE 3.1.xS through 3.4.xS before 3.4.5S and 3.5.xS through 3.7.xS before 3.7.2S allows remote attackers to cause a denial of service (device reload) via crafted (1) IPv4 or (2) IPv6 IP SLA packets on UDP port 1167, aka Bug ID CSCuc72594.

The RSVP protocol implementation in Cisco IOS 12.2 and 15.0 through 15.2 and IOS XE 3.1.xS through 3.4.xS before 3.4.5S and 3.5.xS through 3.7.xS before 3.7.2S, when MPLS-TE is enabled, allows remote attackers to cause a denial of service (incorrect memory access and device reload) via a traffic engineering PATH message in an RSVP packet, aka Bug ID CSCtg39957.

The DHCPv6 server in Cisco IOS 12.2 through 12.4 and 15.0 through 15.2 and IOS XE 2.1.x through 2.6.x, 3.1.xS before 3.1.4S, 3.1.xSG and 3.2.xSG before 3.2.5SG, 3.2.xS, 3.2.xXO, 3.3.xS, and 3.3.xSG before 3.3.1SG allows remote attackers to cause a denial of service (device reload) via a malformed DHCPv6 packet, aka Bug ID CSCto57723.