A vulnerability in the DHCP client implementation of Cisco IOS (12.2, 12.4, and 15.0 through 15.6) and Cisco IOS XE (3.3 through 3.7) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability occurs during the parsing of a crafted DHCP packet. An attacker could exploit this vulnerability by sending crafted DHCP packets to an affected device that is configured as a DHCP client. A successful exploit could allow the attacker to cause a reload of an affected device, resulting in a DoS condition. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS or IOS XE Software and using a specific DHCP client configuration. Cisco Bug IDs: CSCuu43892.

A vulnerability in the Layer 2 Tunneling Protocol (L2TP) parsing function of Cisco IOS (12.0 through 12.4 and 15.0 through 15.6) and Cisco IOS XE (3.1 through 3.18) could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to insufficient validation of L2TP packets. An attacker could exploit this vulnerability by sending a crafted L2TP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS or Cisco IOS XE Software if the L2TP feature is enabled for the device and the device is configured as an L2TP Version 2 (L2TPv2) or L2TP Version 3 (L2TPv3) endpoint. By default, the L2TP feature is not enabled. Cisco Bug IDs: CSCuy82078.

The AAA service in Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 2.1 through 3.18 and 16.2 allows remote attackers to cause a denial of service (device reload) via a failed SSH connection attempt that is mishandled during generation of an error-log message, aka Bug ID CSCuy87667.

The DNS forwarder in Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 3.1 through 3.15 allows remote attackers to obtain sensitive information from process memory or cause a denial of service (data corruption or device reload) via a crafted DNS response, aka Bug ID CSCup90532.

Cisco IOS 12.2 through 12.4 and 15.0 through 15.6 and IOS XE 3.1 through 3.17 and 16.2 allow remote attackers to cause a denial of service (device reload) via crafted fields in an H.323 message, aka Bug ID CSCux04257.

Cisco IOS 15.2 through 15.6 and IOS XE 3.6 through 3.17 and 16.1 allow remote attackers to cause a denial of service (device restart) via a malformed IPv6 Protocol Independent Multicast (PIM) register packet, aka Bug ID CSCuy16399.

Cisco IOS 12.4 and 15.0 through 15.6 and IOS XE 3.1 through 3.18 and 16.1 allow remote attackers to cause a denial of service (memory consumption or device reload) via fragmented IKEv1 packets, aka Bug ID CSCuy47382.

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 Data in Motion (DMo) application in Cisco IOS 15.6(1)T and IOS XE, when the IOx feature set is enabled, allows remote attackers to cause a denial of service via a crafted packet, aka Bug IDs CSCuy82904, CSCuy82909, and CSCuy82912.

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.

The Wide Area Application Services (WAAS) Express implementation in Cisco IOS 15.1 through 15.5 allows remote attackers to cause a denial of service (device reload) via a crafted TCP segment, aka Bug ID CSCuq59708.

The SSHv2 functionality in Cisco IOS 15.2, 15.3, 15.4, and 15.5 and IOS XE 3.6E before 3.6.3E, 3.7E before 3.7.1E, 3.10S before 3.10.6S, 3.11S before 3.11.4S, 3.12S before 3.12.3S, 3.13S before 3.13.3S, and 3.14S before 3.14.1S does not properly implement RSA authentication, which allows remote attackers to obtain login access by leveraging knowledge of a username and the associated public key, aka Bug ID CSCus73013.

The Authentication Proxy feature in Cisco IOS does not properly handle invalid AAA return codes from RADIUS and TACACS+ servers, which allows remote attackers to bypass authentication in opportunistic circumstances via a connection attempt that triggers an invalid code, as demonstrated by a connection attempt with a blank password, aka Bug IDs CSCuo09400 and CSCun16016.

Race condition in the Common Classification Engine (CCE) in the Measurement, Aggregation, and Correlation Engine (MACE) implementation in Cisco IOS 15.4(2)T3 and earlier allows remote attackers to cause a denial of service (device reload) via crafted network traffic that triggers improper handling of the timing of process switching and Cisco Express Forwarding (CEF) switching, aka Bug ID CSCuj96752.

Race condition in the object-group ACL feature in Cisco IOS 15.5(2)T and earlier allows remote attackers to bypass intended access restrictions via crafted network traffic that triggers improper handling of the timing of process switching and Cisco Express Forwarding (CEF) switching, aka Bug ID CSCun21071.

Race condition in the Measurement, Aggregation, and Correlation Engine (MACE) implementation in Cisco IOS 15.4(2)T3 and earlier allows remote attackers to cause a denial of service (device reload) via crafted network traffic that triggers improper handling of the timing of process switching and Cisco Express Forwarding (CEF) switching, aka Bug ID CSCul48736.

The Zone-Based Firewall implementation in Cisco IOS 15.4(2)T3 and earlier allows remote attackers to cause a denial of service (device reload) via crafted network traffic that triggers incorrect kernel-timer handling, aka Bug ID CSCuh25672.

The Temporal Key Integrity Protocol (TKIP) implementation in unspecified Cisco products and other vendors' products, as used in WPA and WPA2 on Wi-Fi networks, has insufficient countermeasures against certain crafted and replayed packets, which makes it easier for remote attackers to decrypt packets from an access point (AP) to a client and spoof packets from an AP to a client, and conduct ARP poisoning attacks or other attacks, as demonstrated by tkiptun-ng.

Unspecified vulnerability in the VLAN Trunking Protocol (VTP) implementation on Cisco IOS and CatOS, when the VTP operating mode is not transparent, allows remote attackers to cause a denial of service (device reload or hang) via a crafted VTP packet sent to a switch interface configured as a trunk port.