A vulnerability in the Cisco Webex Player for Webex Recording Format (WRF) files could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. An attacker could exploit this vulnerability by sending a user a link or email attachment with a malicious WRF file and persuading the user to open the file in the Cisco Webex Player. A successful exploit could cause the affected player to crash, resulting in a DoS condition. For more information about this vulnerability, see the Details section of this security advisory.

A vulnerability in the Cisco Fabric Services component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, remote attacker to obtain sensitive information from memory or cause a denial of service (DoS) condition on the affected product. The vulnerability exists because the affected software insufficiently validates header values in Cisco Fabric Services packets. An attacker could exploit this vulnerability by sending a crafted Cisco Fabric Services packet to an affected device. A successful exploit could allow the attacker to cause a buffer overread condition, which could allow the attacker to obtain sensitive information from memory or cause a DoS condition on the affected product. This vulnerability affects Firepower 4100 Series Next-Generation Firewalls, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Switches, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvd69957, CSCve02435, CSCve04859, CSCve41536, CSCve41538, CSCve41559.

A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol component of Cisco Wireless LAN Controller (WLC) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper input validation on fields within CAPWAP Discovery Request packets by the affected device. An attacker could exploit this vulnerability by sending malicious CAPWAP Discovery Request packets to the Cisco WLC Software. A successful exploit could allow the attacker to cause the Cisco WLC Software to disconnect associated access points (APs). While the APs disconnect and reconnect, service will be unavailable for a brief period of time, resulting in a DoS condition.

A vulnerability in Cisco AMP for Endpoints Mac Connector Software installed on Apple macOS 10.12 could allow an unauthenticated, remote attacker to cause a kernel panic on an affected system, resulting in a denial of service (DoS) condition. The vulnerability exists if the affected software is running in Block network conviction mode. Exploitation could occur if the system that is running the affected software starts a server process and an address in the IP blacklist cache of the affected software attempts to connect to the affected system. A successful exploit could allow the attacker to cause a kernel panic on the system that is running the affected software, resulting in a DoS condition. Cisco Bug IDs: CSCvk08192.

A vulnerability in the HTTP remote procedure call (RPC) service of set-top box (STB) receivers manufactured by Cisco for Yes could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability exists because the firmware of an affected device fails to handle certain XML values that are passed to the HTTP RPC service listening on the local subnet of the device. An attacker could exploit this vulnerability by submitting a malformed request to an affected device. A successful attack could cause the affected device to restart, resulting in a DoS condition. Yes has updated the affected devices with firmware that addresses this vulnerability. Customers are not required to take action. Vulnerable Products: This vulnerability affects YesMaxTotal, YesMax HD, and YesQuattro STB devices. Cisco Bug IDs: CSCvd08812.

A vulnerability in the TCP throttling process for the GUI of the Cisco Identity Services Engine (ISE) 2.1(0.474) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device where the ISE GUI may fail to respond to new or established connection requests. The vulnerability is due to insufficient TCP rate limiting protection on the GUI. An attacker could exploit this vulnerability by sending the affected device a high rate of TCP connections to the GUI. An exploit could allow the attacker to cause the GUI to stop responding while the high rate of connections is in progress. Cisco Bug IDs: CSCvc81803.

A "Cisco Firepower Threat Defense 6.0.0 through 6.2.2 and Cisco ASA with FirePOWER Module Denial of Service" vulnerability in the access control policy of Cisco Firepower System Software could allow an authenticated, remote attacker to cause an affected system to stop inspecting and processing packets, resulting in a denial of service (DoS) condition. The vulnerability is due to improper SSL policy handling by the affected software when packets are passed through the sensing interfaces of an affected system. An attacker could exploit this vulnerability by sending crafted packets through a targeted system. This vulnerability affects Cisco Firepower System Software that is configured with the SSL policy feature. Cisco Bug IDs: CSCvc84361.

A vulnerability in the Session Initiation Protocol (SIP) of the Cisco TelePresence Codec (TC) and Collaboration Endpoint (CE) Software could allow an unauthenticated, remote attacker to cause a TelePresence endpoint to reload unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to a lack of flow-control mechanisms within the software. An attacker could exploit this vulnerability by sending a flood of SIP INVITE packets to the affected device. An exploit could allow the attacker to impact the availability of services and data of the device, including a complete DoS condition. This vulnerability affects the following Cisco TC and CE platforms when running software versions prior to TC 7.3.8 and CE 8.3.0. Cisco Bug IDs: CSCux94002.

A vulnerability in the Session Initiation Protocol (SIP) implementation of Cisco IP Phone 8851 11.0(0.1) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to an abnormal SIP message. An attacker could exploit this vulnerability by manipulating the CANCEL packet. An exploit could allow the attacker to cause a disruption of service to the phone. Cisco Bug IDs: CSCvc34795.

Multiple Cisco products are affected by a vulnerability in local file management for certain system log files of Cisco collaboration products that could allow an unauthenticated, remote attacker to cause high disk utilization, resulting in a denial of service (DoS) condition. The vulnerability occurs because a certain system log file does not have a maximum size restriction. Therefore, the file is allowed to consume the majority of available disk space on the appliance. An attacker could exploit this vulnerability by sending crafted remote connection requests to the appliance. 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 application functions could operate abnormally, making the appliance unstable. This vulnerability affects the following Cisco Voice Operating System (VOS)-based products: Emergency Responder, Finesse, Hosted Collaboration Mediation Fulfillment, MediaSense, Prime License Manager, SocialMiner, Unified Communications Manager (UCM), Unified Communications Manager IM and Presence Service (IM&P - earlier releases were known as Cisco Unified Presence), Unified Communication Manager Session Management Edition (SME), Unified Contact Center Express (UCCx), Unified Intelligence Center (UIC), Unity Connection, Virtualized Voice Browser. This vulnerability also affects Prime Collaboration Assurance and Prime Collaboration Provisioning. Cisco Bug IDs: CSCvd10872, CSCvf64322, CSCvf64332, CSCvi29538, CSCvi29543, CSCvi29544, CSCvi29546, CSCvi29556, CSCvi29571, CSCvi31738, CSCvi31741, CSCvi31762, CSCvi31807, CSCvi31818, CSCvi31823.

A vulnerability in the DNS code of Cisco ASA Software could allow an unauthenticated, remote attacker to cause an affected device to reload or corrupt the information present in the device's local DNS cache. The vulnerability is due to a flaw in handling crafted DNS response messages. An attacker could exploit this vulnerability by triggering a DNS request from the Cisco ASA Software and replying with a crafted response. A successful exploit could cause the device to reload, resulting in a denial of service (DoS) condition or corruption of the local DNS cache information. Note: Only traffic directed to the affected device can be used to exploit this vulnerability. This vulnerability affects Cisco ASA Software configured in routed or transparent firewall mode and single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic. This vulnerability affects Cisco ASA Software running on the following products: Cisco ASA 1000V Cloud Firewall, Cisco ASA 5500 Series Adaptive Security Appliances, Cisco ASA 5500-X Series Next-Generation Firewalls, Cisco ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Cisco Adaptive Security Virtual Appliance (ASAv), Cisco Firepower 9300 ASA Security Module, Cisco ISA 3000 Industrial Security Appliance. Fixed versions: 9.1(7.12) 9.2(4.18) 9.4(3.12) 9.5(3.2) 9.6(2.2). Cisco Bug IDs: CSCvb40898.

A vulnerability in the IPsec code of Cisco ASA Software could allow an authenticated, remote attacker to cause a reload of the affected system. The vulnerability is due to improper parsing of malformed IPsec packets. An attacker could exploit this vulnerability by sending malformed IPsec packets to the affected system. Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability affects systems configured in routed firewall mode only and in single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic. An attacker needs to establish a valid IPsec tunnel before exploiting this vulnerability. This vulnerability affects Cisco ASA Software running on the following products: Cisco ASA 1000V Cloud Firewall, Cisco ASA 5500 Series Adaptive Security Appliances, Cisco ASA 5500-X Series Next-Generation Firewalls, Cisco ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Cisco Adaptive Security Virtual Appliance (ASAv), Cisco Firepower 9300 ASA Security Module, Cisco ISA 3000 Industrial Security Appliance. Fixed versions: 9.1(7.8) 9.2(4.15) 9.4(4) 9.5(3.2) 9.6(2). Cisco Bug IDs: CSCun16158.

A vulnerability in the ingress UDP packet processing functionality of Cisco Virtualized Packet Core-Distributed Instance (VPC-DI) Software 19.2 through 21.0 could allow an unauthenticated, remote attacker to cause both control function (CF) instances on an affected system to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient handling of user-supplied data by the affected software. An attacker could exploit this vulnerability by sending crafted UDP packets to the distributed instance (DI) network addresses of both CF instances on an affected system. A successful exploit could allow the attacker to cause an unhandled error condition on the affected system, which would cause the CF instances to reload and consequently cause the entire VPC to reload, resulting in the disconnection of all subscribers and a DoS condition on the affected system. This vulnerability can be exploited via IPv4 traffic only. Cisco Bug IDs: CSCvc01665 CSCvc35565.

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE 3.16 could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to a race condition that could occur when the affected software processes an SNMP read request that contains certain criteria for a specific object ID (OID) and an active crypto session is disconnected on an affected device. An attacker who can authenticate to an affected device could trigger this vulnerability by issuing an SNMP request for a specific OID on the device. A successful exploit will cause the device to restart due to an attempt to access an invalid memory region. The attacker does not control how or when crypto sessions are disconnected on the device. Cisco Bug IDs: CSCvb94392.

A vulnerability in the TCP throttling process for Cisco IoT Field Network Director (IoT-FND) could allow an unauthenticated, remote attacker to cause the system to consume additional memory, eventually forcing the device to restart, aka Memory Exhaustion. The vulnerability is due to insufficient rate-limiting protection. An attacker could exploit this vulnerability by sending a high rate of TCP packets to a specific group of open listening ports on a targeted device. An exploit could allow the attacker to cause the system to consume additional memory. If enough available memory is consumed, the system will restart, creating a temporary denial of service (DoS) condition. The DoS condition will end after the device has finished the restart process. This vulnerability affects the following Cisco products: Connected Grid Network Management System, if running a software release prior to IoT-FND Release 4.0; IoT Field Network Director, if running a software release prior to IoT-FND Release 4.0. Cisco Bug IDs: CSCvc77164.

A vulnerability in the TCP connection handling functionality of Cisco Remote Expert Manager Software 11.0.0 could allow an unauthenticated, remote attacker to disable TCP ports and cause a denial of service (DoS) condition on an affected system. The vulnerability is due to a lack of rate-limiting functionality in the TCP Listen application of the affected software. An attacker could exploit this vulnerability by sending a crafted TCP traffic stream in which specific types of TCP packets are flooded to an affected device, for example a TCP packet stream in which the TCP FIN bit is set in all the TCP packets. A successful exploit could allow the attacker to cause certain TCP listening ports on the affected system to stop accepting incoming connections for a period of time or until the affected device is restarted, resulting in a DoS condition. In addition, system resources, such as CPU and memory, could be exhausted during the attack. Cisco Bug IDs: CSCva29806.

A vulnerability in the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) code of Cisco ASA Software could allow an unauthenticated, remote attacker to cause a reload of the affected system. The vulnerability is due to improper parsing of crafted SSL or TLS packets. An attacker could exploit this vulnerability by sending a crafted packet to the affected system. Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability affects systems configured in routed and transparent firewall mode and in single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic. A valid SSL or TLS session is needed to exploit this vulnerability. This vulnerability affects Cisco ASA Software running on the following products: Cisco ASA 1000V Cloud Firewall, Cisco ASA 5500 Series Adaptive Security Appliances, Cisco ASA 5500-X Series Next-Generation Firewalls, Cisco ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Cisco Adaptive Security Virtual Appliance (ASAv), Cisco Firepower 9300 ASA Security Module, Cisco ISA 3000 Industrial Security Appliance. Fixed versions: 8.4(7.31) 9.0(4.39) 9.1(7) 9.2(4.6) 9.3(3.8) 9.4(2) 9.5(2). Cisco Bug IDs: CSCuv48243.

A vulnerability in SMART-SSL Accelerator functionality for Cisco Wide Area Application Services (WAAS) 6.2.1, 6.2.1a, and 6.2.3a could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition where the WAN optimization could stop functioning while the process restarts. The vulnerability is due to a Secure Sockets Layer/Transport Layer Security (SSL/TLS) alert being incorrectly handled when in a specific SSL/TLS connection state. An attacker could exploit this vulnerability by establishing a SMART-SSL connection through the targeted device. The attacker would then send a crafted stream of SSL/TLS traffic. An exploit could allow the attacker to cause a DoS condition where WAN optimization could stop processing traffic for a short period of time. Cisco Bug IDs: CSCvb71133.

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.

A vulnerability in the TCP normalizer of Cisco Adaptive Security Appliance (ASA) Software (8.0 through 8.7 and 9.0 through 9.6) and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause Cisco ASA and FTD to drop any further incoming traffic on all interfaces, resulting in a denial of service (DoS) condition. The vulnerability is due to improper limitation of the global out-of-order TCP queue for specific block sizes. An attacker could exploit this vulnerability by sending a large number of unique permitted TCP connections with out-of-order segments. An exploit could allow the attacker to exhaust available blocks in the global out-of-order TCP queue, causing the dropping of any further incoming traffic on all interfaces and resulting in a DoS condition. Cisco Bug IDs: CSCvb46321.

A vulnerability in the Stream Control Transmission Protocol (SCTP) decoder of the Cisco NetFlow Generation Appliance (NGA) with software before 1.1(1a) could allow an unauthenticated, remote attacker to cause the device to hang or unexpectedly reload, causing a denial of service (DoS) condition. The vulnerability is due to incomplete validation of SCTP packets being monitored on the NGA data ports. An attacker could exploit this vulnerability by sending malformed SCTP packets on a network that is monitored by an NGA data port. SCTP packets addressed to the IP address of the NGA itself will not trigger this vulnerability. An exploit could allow the attacker to cause the appliance to become unresponsive or reload, causing a DoS condition. User interaction could be needed to recover the device using the reboot command from the CLI. The following Cisco NetFlow Generation Appliances are vulnerable: NGA 3140, NGA 3240, NGA 3340. Cisco Bug IDs: CSCvc83320.

A vulnerability in the web user interface of Cisco IOS XE 3.1 through 3.17 could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to insufficient resource handling by the affected software when the web user interface is under a high load. An attacker could exploit this vulnerability by sending a high number of requests to the web user interface of the affected software. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. To exploit this vulnerability, the attacker must have access to the management interface of the affected software, which is typically connected to a restricted management network. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software, if the web user interface of the software is enabled. By default, the web user interface is not enabled. Cisco Bug IDs: CSCup70353.

A vulnerability in the Event Management Service daemon (emsd) of Cisco IOS XR routers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. The vulnerability is due to improper handling of gRPC requests. An attacker could exploit this vulnerability by repeatedly sending unauthenticated gRPC requests to the affected device. A successful exploit could allow the attacker to crash the device in such a manner that manual intervention is required to recover. This vulnerability affects all Cisco IOS XR platforms that are running release 6.1.1 of Cisco IOS XR Software when the gRPC service is enabled on the device. The gRPC service is not enabled by default. Cisco Bug IDs: CSCvb14441.

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 punt code of Cisco IOS XR Software running on Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to cause the affected line card to reboot. This vulnerability is due to incorrect handling of specific Ethernet frames that cause a spin loop that can make the network processors unresponsive. An attacker could exploit this vulnerability by sending specific types of Ethernet frames on the segment where the affected line cards are attached. A successful exploit could allow the attacker to cause the affected line card to reboot.

A vulnerability in the received packet parser of Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) software could allow an unauthenticated, remote attacker to cause a reload of the affected system, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient size validation of user-supplied data. An attacker could exploit this vulnerability by sending crafted H.224 data in Real-Time Transport Protocol (RTP) packets in an H.323 call. An exploit could allow the attacker to overflow a buffer in a cache that belongs to the received packet parser, which will result in a crash of the application, resulting in a DoS condition. All versions of Cisco Expressway Series Software and Cisco TelePresence VCS Software prior to version X8.8.2 are vulnerable. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Cisco Bug IDs: CSCus99263.

Multiple vulnerabilities in the ingress packet processing function of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the Local Packet Transport Services (LPTS) ingress frame-processing functionality of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause one of the LPTS processes on an affected system to restart unexpectedly, resulting in a brief denial of service (DoS) condition. The vulnerability is due to incomplete LPTS frame validation by the affected software. An attacker could exploit this vulnerability by sending crafted XML requests to the management interface of an affected system. A successful exploit could allow the attacker to cause one of the LPTS processes on the affected system to restart unexpectedly, which would impact LPTS traffic and cause a brief DoS condition while the process restarts. Cisco Bug IDs: CSCvf76332.

A vulnerability in how Cisco Firepower Threat Defense (FTD) Software handles session timeouts for management connections could allow an unauthenticated, remote attacker to cause a buildup of remote management connections to an affected device, which could result in a denial of service (DoS) condition. The vulnerability exists because the default session timeout period for specific to-the-box remote management connections is too long. An attacker could exploit this vulnerability by sending a large and sustained number of crafted remote management connections to an affected device, resulting in a buildup of those connections over time. A successful exploit could allow the attacker to cause the remote management interface or Cisco Firepower Device Manager (FDM) to stop responding and cause other management functions to go offline, resulting in a DoS condition. The user traffic that is flowing through the device would not be affected, and the DoS condition would be isolated to remote management only.

A vulnerability in the Internet Key Exchange version 1 (IKEv1) feature 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. The vulnerability is due to improper management of system memory. An attacker could exploit this vulnerability by sending malicious IKEv1 traffic to an affected device. A successful exploit could allow the attacker to cause a DoS condition on the affected device.

A vulnerability in Cisco SD-WAN Solution Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper validation of fields in Cisco SD-WAN peering messages that are encapsulated in UDP packets. An attacker could exploit this vulnerability by sending crafted UDP messages to the targeted system. A successful exploit could allow the attacker to cause services on the device to fail, resulting in a DoS condition that could impact the targeted device and other devices that depend on it.

A vulnerability in the data plane IP fragment handler of the Cisco Adaptive Security Appliance (ASA) CX Context-Aware Security module could allow an unauthenticated, remote attacker to cause the CX module to be unable to process further traffic, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of IP fragments. An attacker could exploit this vulnerability by sending crafted fragmented IP traffic across the CX module. An exploit could allow the attacker to exhaust free packet buffers in shared memory (SHM), causing the CX module to be unable to process further traffic, resulting in a DoS condition. This vulnerability affects all versions of the ASA CX Context-Aware Security module. Cisco has not released and will not release software updates that address this vulnerability. There are no workarounds that address this vulnerability. Cisco Bug IDs: CSCva62946.