The Certificate Authority Proxy Function (CAPF) service in Cisco Unified Communications Manager 5.x before 5.1(3e) and 6.x before 6.1(3) allows remote attackers to cause a denial of service (voice service outage) by sending malformed input over a TCP session in which the "client terminates prematurely."

A vulnerability in the connection handling function in Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper traffic handling when platform limits are reached. An attacker could exploit this vulnerability by sending a high rate of UDP traffic through an affected device. A successful exploit could allow the attacker to cause all new, incoming connections to be dropped, resulting in a DoS condition.

A vulnerability in the implementation of Border Gateway Protocol (BGP) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected system. The vulnerability is due to incorrect processing of certain BGP update messages. An attacker could exploit this vulnerability by sending BGP update messages that include a specific set of 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 from explicitly defined peers only. To exploit this vulnerability, 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 within the Endpoint Learning feature of Cisco Nexus 9000 Series Switches running in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an endpoint device in certain circumstances. The vulnerability is due to improper endpoint learning when packets are received on a specific port from outside the ACI fabric and destined to an endpoint located on a border leaf when Disable Remote Endpoint Learning has been enabled. This can result in a Remote (XR) entry being created for the impacted endpoint that will become stale if the endpoint migrates to a different port or leaf switch. This results in traffic not reaching the impacted endpoint until the Remote entry can be relearned by another mechanism.

A vulnerability in the remote access VPN session manager of Cisco Adaptive Security Appliance (ASA) Software could allow a unauthenticated, remote attacker to cause a denial of service (DoS) condition on the remote access VPN services. The vulnerability is due to an issue with the remote access VPN session manager. An attacker could exploit this vulnerability by requesting an excessive number of remote access VPN sessions. An exploit could allow the attacker to cause a DoS condition.

Cisco IOS 11.1(x) through 11.3(x) and 12.0(x) through 12.2(x), when configured for BGP routing, allows remote attackers to cause a denial of service (device reload) via malformed BGP (1) OPEN or (2) UPDATE messages.

A vulnerability in the network stack of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability exists because the software improperly releases resources when it processes certain IPv6 packets that are destined to an affected device. An attacker could exploit this vulnerability by sending multiple crafted IPv6 packets to an affected device. A successful exploit could cause the network stack to run out of available buffers, impairing operations of control plane and management plane protocols and resulting in a DoS condition. Manual intervention would be required to restore normal operations on the affected device. For more information about the impact of this vulnerability, see the Details section of this advisory.

A vulnerability in the implementation of Border Gateway Protocol (BGP) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain BGP update messages. An attacker could exploit this vulnerability by sending BGP update messages that include a specific, malformed attribute 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 this vulnerability, 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.

Multiple vulnerabilities exist in the Cisco Webex Network Recording Player for Advanced Recording Format (ARF) and Webex Recording Format (WRF) files. An attacker could exploit these vulnerabilities by providing a user with a malicious .arf or .wrf file via email or URL and convincing the user to launch the file in the Webex recording players. Exploitation of these vulnerabilities could cause an affected player to crash, resulting in a denial of service (DoS) condition. The Cisco Webex players are applications that are used to play back Webex meetings that have been recorded by an online meeting attendee. The Webex Network Recording Player for .arf files can be automatically installed when the user accesses a recording that is hosted on a Webex server. The Webex Player for .wrf files can be downloaded manually. These vulnerabilities affect ARF and WRF recording players available from Cisco Webex Meetings Suite sites, Cisco Webex Meetings Online sites, and Cisco Webex Meetings Server. Cisco Bug IDs: CSCvh70253, CSCvh70268, CSCvh72272, CSCvh72281, CSCvh72285, CSCvi60477, CSCvi60485, CSCvi60490, CSCvi60520, CSCvi60529, CSCvi60533.

A vulnerability in the Secure Sockets Layer (SSL) Engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper error handling while processing SSL traffic. An attacker could exploit this vulnerability by sending a large volume of crafted SSL traffic to the vulnerable device. A successful exploit could allow the attacker to degrade the device performance by triggering a persistent high CPU utilization condition. Cisco Bug IDs: CSCvh89340.

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 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 VXLAN Operation, Administration, and Maintenance (OAM) feature of Cisco NX-OS Software, known as NGOAM, could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of specific packets with a Transparent Interconnection of Lots of Links (TRILL) OAM EtherType. An attacker could exploit this vulnerability by sending crafted packets, including the TRILL OAM EtherType of 0x8902, to a device that is part of a VXLAN Ethernet VPN (EVPN) fabric. A successful exploit could allow the attacker to cause an affected device to experience high CPU usage and consume excessive system resources, which may result in overall control plane instability and cause the affected device to reload. Note: The NGOAM feature is disabled by default.

The Locator/ID Separation Protocol (LISP) implementation in Cisco IOS 15.3(3)S and earlier and IOS XE does not properly validate parameters in ITR control messages, which allows remote attackers to cause a denial of service (CEF outage and packet drops) via malformed messages, aka Bug ID CSCun73782.

Cisco Unified Communications Manager (aka CUCM or Unified CM) allows remote attackers to cause a denial of service (service restart) via a crafted SIP message, aka Bug ID CSCub54349.

A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause an NX-API system process to unexpectedly restart. The vulnerability is due to incorrect validation of the HTTP header of a request that is sent to the NX-API. An attacker could exploit this vulnerability by sending a crafted HTTP request to the NX-API on an affected device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition in the NX-API service; however, the Cisco NX-OS device itself would still be available and passing network traffic. Note: The NX-API feature is disabled by default.

Cisco IOS before 15.3(2)T, when scansafe is enabled, allows remote attackers to cause a denial of service (latency) via SYN packets that are not accompanied by SYN-ACK packets from the Scan Safe Tower, aka Bug ID CSCub85451.

Cisco IOS before 15.3(1)T on Cisco 2900 devices, when a VWIC2-2MFT-T1/E1 card is configured for TDM/HDLC mode, allows remote attackers to cause a denial of service (serial-interface outage) via certain Frame Relay traffic, aka Bug ID CSCub13317.

The BGP implementation in Cisco NX-OS does not properly filter AS paths, which allows remote attackers to cause a denial of service (BGP service reset and resync) via a malformed UPDATE message, aka Bug ID CSCtn13065.