The Packet Data Network Gateway (aka PGW) component on Cisco ASR 5000 devices with software 15.0(912), 15.0(935), and 15.0(938) allows remote attackers to cause a denial of service (Session Manager outage) via malformed fields in an IP packet, aka Bug ID CSCut38476.

The packet-reassembly implementation in Cisco IOS XE 3.13S and earlier allows remote attackers to cause a denial of service (CPU consumption or packet loss) via fragmented (1) IPv4 or (2) IPv6 packets that trigger ATTN-3-SYNC_TIMEOUT errors after reassembly failures, aka Bug ID CSCuo37957.

A vulnerability in the TCP ingress handler for the data interfaces that are configured with management access to Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an increase in CPU and memory usage, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient ingress TCP rate limiting for TCP ports 22 (SSH) and 443 (HTTPS). An attacker could exploit this vulnerability by sending a crafted, steady stream of TCP traffic to port 22 or 443 on the data interfaces that are configured with management access to the affected device.

The Local Packet Transport Services (LPTS) implementation in Cisco IOS XR 5.1.2, 5.1.3, 5.2.1, and 5.2.2 on ASR9k devices makes incorrect decisions about the opening of TCP and UDP ports during the processing of flow base entries, which allows remote attackers to cause a denial of service (resource consumption) by sending traffic to these ports continuously, aka Bug ID CSCur88273.

A vulnerability in the Shell Access Filter feature of Cisco Firepower Management Center (FMC), when used in conjunction with remote authentication, could allow an unauthenticated, remote attacker to cause high disk utilization, resulting in a denial of service (DoS) condition. The vulnerability occurs because the configuration of the Shell Access Filter, when used with a specific type of remote authentication, can cause a system file to have unbounded writes. An attacker could exploit this vulnerability by sending a steady stream of remote authentication requests to the appliance when the specific configuration is applied. Successful exploitation could allow the attacker to increase the size of a system log file so that it consumes most of the disk space. The lack of available disk space could lead to a DoS condition in which the device functions could operate abnormally, making the device unstable.

A vulnerability in the DHCP server of Cisco Prime Network Registrar could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient input validation of incoming DHCP traffic. An attacker could exploit this vulnerability by sending a crafted DHCP request to an affected device. A successful exploit could allow the attacker to cause a restart of the DHCP server process, causing a DoS condition.

A vulnerability in the IPv6 packet processing engine of Cisco Small Business Smart and Managed Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient validation of incoming IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet through an affected device. A successful exploit could allow the attacker to cause the switch management CLI to stop responding, resulting in a DoS condition. This vulnerability is specific to IPv6 traffic. IPv4 traffic is not affected.

A vulnerability in the Protocol Independent Multicast (PIM) feature for IPv6 networks (PIM6) of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper error handling when processing inbound PIM6 packets. An attacker could exploit this vulnerability by sending multiple crafted PIM6 packets to an affected device. A successful exploit could allow the attacker to cause the PIM6 application to leak system memory. Over time, this memory leak could cause the PIM6 application to stop processing legitimate PIM6 traffic, leading to a DoS condition on the affected device.

A vulnerability in the PDF archive parsing module in Clam AntiVirus (ClamAV) Software versions 0.101 - 0.102.2 could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. The vulnerability is due to a stack buffer overflow read. An attacker could exploit this vulnerability by sending a crafted PDF file to an affected device. An exploit could allow the attacker to cause the ClamAV scanning process crash, resulting in a denial of service condition.

A vulnerability in the ssl_inspection component of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to crash Snort instances. The vulnerability is due to insufficient input validation in the ssl_inspection component. An attacker could exploit this vulnerability by sending a malformed TLS packet through a Cisco Adaptive Security Appliance (ASA). A successful exploit could allow the attacker to crash a Snort instance, resulting in a denial of service (DoS) condition.

A vulnerability in the SSL/TLS session handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory leak when closing SSL/TLS connections in a specific state. An attacker could exploit this vulnerability by establishing several SSL/TLS sessions and ensuring they are closed under certain conditions. A successful exploit could allow the attacker to exhaust memory resources in the affected device, which would prevent it from processing new SSL/TLS connections, resulting in a DoS. Manual intervention is required to recover an affected device.

A vulnerability in the licensing service of Cisco Firepower Management Center (FMC) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.The vulnerability is due to improper handling of system resource values by the affected system. An attacker could exploit this vulnerability by sending malicious requests to the targeted system. A successful exploit could allow the attacker to cause the affected system to become unresponsive, resulting in a DoS condition and preventing the management of dependent devices.

A vulnerability in the ARJ archive parsing module in Clam AntiVirus (ClamAV) Software versions 0.102.2 could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. The vulnerability is due to a heap buffer overflow read. An attacker could exploit this vulnerability by sending a crafted ARJ file to an affected device. An exploit could allow the attacker to cause the ClamAV scanning process crash, resulting in a denial of service condition.

A vulnerability in the OSPF Version 2 (OSPFv2) implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to incomplete input validation when the affected software processes certain OSPFv2 packets with Link-Local Signaling (LLS) data. An attacker could exploit this vulnerability by sending a malformed OSPFv2 packet to an affected device. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition.

A vulnerability in the SSL VPN negotiation process for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to inefficient direct memory access (DMA) memory management during the negotiation phase of an SSL VPN connection. An attacker could exploit this vulnerability by sending a steady stream of crafted Datagram TLS (DTLS) traffic to an affected device. A successful exploit could allow the attacker to exhaust DMA memory on the device and cause a DoS condition.

The DNS implementation in Cisco Videoscape Distribution Suite for Internet Streaming (VDS-IS) 3.2(1) allows remote attackers to cause a denial of service (CPU consumption and network-resource consumption) via crafted packets, aka Bug ID CSCun15911.

A vulnerability in the IPv6 packet processing engine of Cisco Small Business Smart and Managed Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient validation of incoming IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet through an affected device. A successful exploit could allow the attacker to cause an unexpected reboot of the switch, leading to a DoS condition. This vulnerability is specific to IPv6 traffic. IPv4 traffic is not affected.

A vulnerability in the Simple Network Management Protocol (SNMP) input packet processor of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to restart unexpectedly. The vulnerability is due to a lack of sufficient memory management protections under heavy SNMP polling loads. An attacker could exploit this vulnerability by sending a high rate of SNMP requests to the SNMP daemon through the management interface on an affected device. A successful exploit could allow the attacker to cause the SNMP daemon process to consume a large amount of system memory over time, which could then lead to an unexpected device restart, causing a denial of service (DoS) condition. This vulnerability affects all versions of SNMP.

A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol handler of Cisco Wireless LAN Controller (WLC) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient validation of CAPWAP packets. An attacker could exploit this vulnerability by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to restart, resulting in a DoS condition.

A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Firepower Threat Defense (FTD) Software when running on the Cisco Firepower 1000 Series platform could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition on an affected device. The vulnerability is due to a communication error between internal functions. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message to an affected device. A successful exploit could allow the attacker to cause a buffer underrun, which leads to a crash. The crash causes the affected device to reload.

A vulnerability in the VPN System Logging functionality for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a memory leak that can deplete system memory over time, which can cause unexpected system behaviors or device crashes. The vulnerability is due to the system memory not being properly freed for a VPN System Logging event generated when a VPN session is created or deleted. An attacker could exploit this vulnerability by repeatedly creating or deleting a VPN tunnel connection, which could leak a small amount of system memory for each logging event. A successful exploit could allow the attacker to cause system memory depletion, which can lead to a systemwide denial of service (DoS) condition. The attacker does not have any control of whether VPN System Logging is configured or not on the device, but it is enabled by default.

A vulnerability in the IPsec packet processor of Cisco IOS XR Software could allow an unauthenticated remote attacker to cause a denial of service (DoS) condition for IPsec sessions to an affected device. The vulnerability is due to improper handling of packets by the IPsec packet processor. An attacker could exploit this vulnerability by sending malicious ICMP error messages to an affected device that get punted to the IPsec packet processor. A successful exploit could allow the attacker to deplete IPsec memory, resulting in all future IPsec packets to an affected device being dropped by the device. Manual intervention is required to recover from this situation.

A vulnerability in DNS over IPv6 packet processing for Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to unexpectedly reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper length validation of a field in an IPv6 DNS packet. An attacker could exploit this vulnerability by sending a crafted DNS query over IPv6, which traverses the affected device. An exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. This vulnerability is specific to DNS over IPv6 traffic only.

A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust memory resources on the affected device, leading to a denial of service (DoS) condition. The vulnerability is due to improper resource management for inbound SSL/TLS connections. An attacker could exploit this vulnerability by establishing multiple SSL/TLS connections with specific conditions to the affected device. A successful exploit could allow the attacker to exhaust the memory on the affected device, causing the device to stop accepting new SSL/TLS connections and resulting in a DoS condition for services on the device that process SSL/TLS traffic. Manual intervention is required to recover an affected device.

Cisco Secure Access Control Server (ACS) 3.2, when configured as a Light Extensible Authentication Protocol (LEAP) RADIUS proxy, allows remote attackers to cause a denial of service (device crash) via certain LEAP authentication requests.

A vulnerability in the Constrained Application Protocol (CoAP) implementation of Cisco IoT Field Network Director could allow an unauthenticated remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient input validation of incoming CoAP traffic. An attacker could exploit this vulnerability by sending a malformed CoAP packet to an affected device. A successful exploit could allow the attacker to force the CoAP server to stop, interrupting communication to the IoT endpoints.

Cisco IOS XR allows remote attackers to cause a denial of service (LISP process reload) by establishing many LISP TCP sessions, aka Bug ID CSCuq90378.

The HTTPS Proxy feature in Cisco AsyncOS before 8.5.3-051 and 9.x before 9.0.0-485 on Web Security Appliance (WSA) devices allows remote attackers to cause a denial of service (service outage) by leveraging certain intranet connectivity and sending a malformed HTTPS request, aka Bug ID CSCuu24840.

The administration interface on Cisco DPQ3925 devices with firmware r1 allows remote attackers to cause a denial of service (device restart) via a crafted HTTP request, aka Bug ID CSCup48105.

A vulnerability in certain IPv4 fragment-processing functions of Cisco Remote PHY Software could allow an unauthenticated, remote attacker to impact traffic passing through a device, potentially causing a denial of service (DoS) condition. The vulnerability is due to the affected software not validating and calculating certain numerical values in IPv4 packets that are sent to an affected device. An attacker could exploit this vulnerability by sending malformed IPv4 traffic to an affected device. A successful exploit could allow the attacker to disrupt the flow of certain IPv4 traffic passing through an affected device, which could result in a DoS condition.

A vulnerability in Address Resolution Protocol (ARP) management of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to prevent an affected device from resolving ARP entries for legitimate hosts on the connected subnets. This vulnerability exists because ARP entries are mismanaged. An attacker could exploit this vulnerability by continuously sending traffic that results in incomplete ARP entries. A successful exploit could allow the attacker to cause ARP requests on the device to be unsuccessful for legitimate hosts, resulting in a denial of service (DoS) condition.

Cisco ONS 15454 controller cards with software 10.0 and earlier allow remote attackers to cause a denial of service (card reload) via a crafted HTTP URI, aka Bug ID CSCun06870.

Memory leak in the gk_circuit_info_do_in_acf function in the H.323 implementation in Cisco IOS before 15.0(1)XA allows remote attackers to cause a denial of service (memory consumption) via a large number of calls over a long duration, as demonstrated by InterZone Clear Token (IZCT) test traffic, aka Bug ID CSCsz72535.

Memory leak in the SIP inspection engine in Cisco Adaptive Security Appliance (ASA) Software allows remote attackers to cause a denial of service (memory consumption and instability) via crafted SIP packets, aka Bug ID CSCuf67469.

Cisco ONS 15454 controller cards with software 9.6 and earlier allow remote attackers to cause a denial of service (flash write outage) via a TCP FIN attack that triggers file-descriptor exhaustion, aka Bug ID CSCug97315.

Cisco ASR 5000 devices with software 16.0(900) allow remote attackers to cause a denial of service (telnetd process restart) via a TELNET connection, aka Bug ID CSCuv25815.

Multiple vulnerabilities in the implementation of Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerabilities are due to incorrect processing of BGP update messages that contain crafted EVPN attributes. An attacker could exploit these vulnerabilities by sending BGP EVPN update messages with malformed attributes to be processed by an affected system. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP traffic only from explicitly defined peers. To exploit these vulnerabilities, the malicious BGP update message would need to come from a configured, valid BGP peer, or would need to be injected by the attacker into the victim's BGP network on an existing, valid TCP connection to a BGP peer.

A vulnerability in the IPv6 traffic processing of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause an unexpected restart of the netstack process on an affected device. The vulnerability is due to improper validation of IPv6 traffic sent through an affected device. An attacker could exploit this vulnerability by sending a malformed IPv6 packet through an affected device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition while the netstack process restarts. A sustained attack could lead to a reboot of the device.

The firewall subsystem in Cisco Identity Services Engine has an incorrect rule for open ports, which allows remote attackers to cause a denial of service (CPU consumption or process crash) via a flood of malformed IP packets, aka Bug ID CSCug94572.

Cisco Catalyst LAN switches running Catalyst 5000 supervisor software allows remote attackers to perform a denial of service by forcing the supervisor module to reload.

Buffer overflow in Cisco 7xx routers through the telnet service.

Cisco ACE A2(3.6) allows log retention DoS.

Cisco IOS 12.2(15) and earlier allows remote attackers to cause a denial of service (refused VTY (virtual terminal) connections), via a crafted TCP connection to the Telnet or reverse Telnet port.