Layer 2 network filtering capabilities such as IPv6 RA guard or ARP inspection can be bypassed using combinations of VLAN 0 headers and LLC/SNAP headers.
Multiple vulnerabilities in the Application Layer Protocol Inspection feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerabilities are due to logical errors during traffic inspection. An attacker could exploit these vulnerabilities by sending a high volume of malicious traffic across an affected device. An exploit could allow the attacker to cause a deadlock condition, resulting in a reload of an affected device. These vulnerabilities affect Cisco ASA Software and Cisco FTD Software configured for Application Layer Protocol Inspection running on the following Cisco products: 3000 Series Industrial Security Appliance (ISA), ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Adaptive Security Virtual Appliance (ASAv), Firepower 2100 Series Security Appliance, Firepower 4100 Series Security Appliance, Firepower 9300 ASA Security Module, FTD Virtual (FTDv). Cisco Bug IDs: CSCve61540, CSCvh23085, CSCvh95456.
A vulnerability in the Virtual Private LAN Service (VPLS) code of Cisco IOS 15.0 through 15.4 for Cisco Catalyst 6800 Series Switches could allow an unauthenticated, adjacent attacker to cause a C6800-16P10G or C6800-16P10G-XL type line card to crash, resulting in a denial of service (DoS) condition. The vulnerability is due to a memory management issue in the affected software. An attacker could exploit this vulnerability by creating a large number of VPLS-generated MAC entries in the MAC address table of an affected device. A successful exploit could allow the attacker to cause a C6800-16P10G or C6800-16P10G-XL type line card to crash, resulting in a DoS condition. This vulnerability affects Cisco Catalyst 6800 Series Switches that are running a vulnerable release of Cisco IOS Software and have a Cisco C6800-16P10G or C6800-16P10G-XL line card in use with Supervisor Engine 6T. To be vulnerable, the device must also be configured with VPLS and the C6800-16P10G or C6800-16P10G-XL line card needs to be the core-facing MPLS interfaces. Cisco Bug IDs: CSCva61927.
The IKE implementation in the WS-IPSEC-3 service module in Cisco IOS 12.2 on Catalyst 6500 devices allows remote authenticated users to cause a denial of service (device reload) by sending a crafted message during IPsec tunnel setup, aka Bug ID CSCur70505.
The HTTP server in Cisco IOS on Catalyst switches does not properly handle TCP socket events, which allows remote attackers to cause a denial of service (device crash) via crafted packets on TCP port (1) 80 or (2) 443, aka Bug ID CSCuc53853.
The DHCP server on Cisco Adaptive Security Appliances (ASA) 5500 series devices, and the ASA Services Module (ASASM) in Cisco Catalyst 6500 series devices, with software 7.0 before 7.2(5.8), 7.1 before 7.2(5.8), 7.2 before 7.2(5.8), 8.0 before 8.0(5.28), 8.1 before 8.1(2.56), 8.2 before 8.2(5.27), 8.3 before 8.3(2.31), 8.4 before 8.4(3.10), 8.5 before 8.5(1.9), and 8.6 before 8.6(1.5) does not properly allocate memory for DHCP packets, which allows remote attackers to cause a denial of service (device reload) via a series of crafted IPv4 packets, aka Bug ID CSCtw84068.
The AAA functionality in the IPv4 SSL VPN implementations on Cisco Adaptive Security Appliances (ASA) 5500 series devices, and the ASA Services Module (ASASM) in Cisco Catalyst 6500 series devices, with software 8.2 before 8.2(5.30) and 8.3 before 8.3(2.34) allows remote attackers to cause a denial of service (device reload) via a crafted authentication response, aka Bug ID CSCtz04566.
The SIP inspection engine on Cisco Adaptive Security Appliances (ASA) 5500 series devices, and the ASA Services Module (ASASM) in Cisco Catalyst 6500 series devices, with software 8.2 before 8.2(5.17), 8.3 before 8.3(2.28), 8.4 before 8.4(2.13), 8.5 before 8.5(1.4), and 8.6 before 8.6(1.5) allows remote attackers to cause a denial of service (device reload) via a crafted SIP media-update packet, aka Bug ID CSCtr63728.
Stack-based buffer overflow in the DCERPC inspection engine on Cisco Adaptive Security Appliances (ASA) 5500 series devices, and the ASA Services Module (ASASM) in Cisco Catalyst 6500 series devices, with software 8.3 before 8.3(2.34), 8.4 before 8.4(4.4), 8.5 before 8.5(1.13), and 8.6 before 8.6(1.3) and the Firewall Services Module (FWSM) 4.1 before 4.1(9) in Cisco Catalyst 6500 series switches and 7600 series routers might allow remote attackers to execute arbitrary code via a crafted DCERPC packet, aka Bug IDs CSCtr21359 and CSCtr27522.