Multiple vulnerabilities in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a DoS condition in the AnyConnect service on an affected device. These vulnerabilities are due to insufficient validation of client-supplied parameters while establishing an SSL VPN session. An attacker could exploit these vulnerabilities by sending a crafted HTTPS request to the VPN server of an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to restart, resulting in the failure of the established SSL VPN connections and forcing remote users to initiate a new VPN connection and reauthenticate. A sustained attack could prevent new SSL VPN connections from being established. Note: When the attack traffic stops, the Cisco AnyConnect VPN server recovers gracefully without requiring manual intervention.

A vulnerability in the DHCPv6 relay agent 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 is due to improper handling of specific fields in a DHCPv6 RELAY-REPLY message. An attacker could exploit this vulnerability by sending a crafted DHCPv6 packet to any IPv6 address that is configured on an affected device. A successful exploit could allow the attacker to cause the dhcp_snoop process to crash and restart multiple times, causing the affected device to reload and resulting in a DoS condition.

A vulnerability in the TLS processing feature of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an issue that occurs when TLS traffic is processed. An attacker could exploit this vulnerability by sending certain TLS traffic over IPv4 through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition and impacting traffic to and through the affected device.

A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to incomplete error checking when parsing an HTTP header. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted web server on a device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.

A vulnerability in the SSL VPN feature for 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 unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to a logic error in memory management when the device is handling SSL VPN connections. An attacker could exploit this vulnerability by sending crafted SSL/TLS packets to the SSL VPN server of the affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

A vulnerability in the Internet Key Exchange version 2 (IKEv2) protocol for VPN termination 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. This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending crafted IKEv2 traffic to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

A vulnerability in the DHCP snooping feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to a crafted IPv4 DHCP request packet being mishandled when endpoint analytics are enabled. An attacker could exploit this vulnerability by sending a crafted DHCP request through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: The attack vector is listed as network because a DHCP relay anywhere on the network could allow exploits from networks other than the adjacent one.

A vulnerability in the Locator ID Separation Protocol (LISP) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. This vulnerability is due to the incorrect handling of LISP packets. An attacker could exploit this vulnerability by sending a crafted LISP packet to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition. Note: This vulnerability could be exploited over either IPv4 or IPv6 transport.

A vulnerability in the SIP call processing function of Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper parsing of SIP messages. An attacker could exploit this vulnerability by sending a crafted SIP message to an affected Cisco Unified CM or Cisco Unified CM SME device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition that interrupts the communications of reliant voice and video devices.

A vulnerability in the Snort 2 and Snort 3 TCP and UDP detection engine of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series Appliances could allow an unauthenticated, remote attacker to cause memory corruption, which could cause the Snort detection engine to restart unexpectedly. This vulnerability is due to improper memory management when the Snort detection engine processes specific TCP or UDP packets. An attacker could exploit this vulnerability by sending crafted TCP or UDP packets through a device that is inspecting traffic using the Snort detection engine. A successful exploit could allow the attacker to restart the Snort detection engine repeatedly, which could cause a denial of service (DoS) condition. The DoS condition impacts only the traffic through the device that is examined by the Snort detection engine. The device can still be managed over the network. Note: Once a memory block is corrupted, it cannot be cleared until the Cisco Firepower 2100 Series Appliance is manually reloaded. This means that the Snort detection engine could crash repeatedly, causing traffic that is processed by the Snort detection engine to be dropped until the device is manually reloaded.

A vulnerability in the External Border Gateway Protocol (eBGP) implementation 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 eBGP traffic is mapped to a shared hardware rate-limiter queue. An attacker could exploit this vulnerability by sending large amounts of network traffic with certain characteristics through an affected device. A successful exploit could allow the attacker to cause eBGP neighbor sessions to be dropped, leading to a DoS condition in the network.

A vulnerability in the Resource Reservation Protocol (RSVP) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to a buffer overflow when processing crafted RSVP packets. An attacker could exploit this vulnerability by sending RSVP traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

A vulnerability in the IPv4 Software-Defined Access (SD-Access) fabric edge node feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause high CPU utilization and stop all traffic processing, resulting in a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of certain IPv4 packets. An attacker could exploit this vulnerability by sending certain IPv4 packets to an affected device. A successful exploit could allow the attacker to cause the device to exhaust CPU resources and stop processing traffic, resulting in a DoS condition.

A vulnerability in the TCP/IP traffic handling function of the Snort Detection Engine of Cisco Firepower Threat Defense (FTD) Software and Cisco FirePOWER Services could allow an unauthenticated, remote attacker to cause legitimate network traffic to be dropped, resulting in a denial of service (DoS) condition. This vulnerability is due to the improper handling of TCP/IP network traffic. An attacker could exploit this vulnerability by sending a large amount of TCP/IP network traffic through the affected device. A successful exploit could allow the attacker to cause the Cisco FTD device to drop network traffic, resulting in a DoS condition. The affected device must be rebooted to resolve the DoS condition.

A vulnerability in the IP packet processing of Cisco Access Point (AP) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient input validation of certain IPv4 packets. An attacker could exploit this vulnerability by sending a crafted IPv4 packet either to or through an affected device. A successful exploit could allow the attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. To successfully exploit this vulnerability, the attacker does not need to be associated with the affected AP. This vulnerability cannot be exploited by sending IPv6 packets.

A vulnerability in the IKEv1 fragmentation code of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a heap underflow, resulting in an affected device reloading. This vulnerability exists because crafted, fragmented IKEv1 packets are not properly reassembled. An attacker could exploit this vulnerability by sending crafted UDP packets to an affected system. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: Only traffic that is directed to the affected system can be used to exploit this vulnerability. This vulnerability can be triggered by IPv4 and IPv6 traffic..

A vulnerability with the handling of MPLS traffic for Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause the netstack process to unexpectedly restart, which could cause the device to stop processing network traffic or to reload. This vulnerability is due to lack of proper error checking when processing an ingress MPLS frame. An attacker could exploit this vulnerability by sending a crafted IPv6 packet that is encapsulated within an MPLS frame to an MPLS-enabled interface of the targeted device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition. Note: The IPv6 packet can be generated multiple hops away from the targeted device and then encapsulated within MPLS. The DoS condition may occur when the NX-OS device processes the packet.

A vulnerability in the VPN and management web servers of the Cisco Adaptive Security Virtual Appliance (ASAv) and Cisco Secure Firewall Threat Defense Virtual (FTDv), formerly Cisco Firepower Threat Defense Virtual, platforms could allow an unauthenticated, remote attacker to cause the virtual devices to run out of system memory, which could cause SSL VPN connection processing to slow down and eventually cease all together. This vulnerability is due to a lack of proper memory management for new incoming SSL/TLS connections on the virtual platforms. An attacker could exploit this vulnerability by sending a large number of new incoming SSL/TLS connections to the targeted virtual platform. A successful exploit could allow the attacker to deplete system memory, resulting in a denial of service (DoS) condition. The memory could be reclaimed slowly if the attack traffic is stopped, but a manual reload may be required to restore operations quickly.

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 TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software operating in transparent mode could allow an unauthenticated, remote attacker to poison MAC address tables, resulting in a denial of service (DoS) vulnerability. This vulnerability is due to incorrect handling of certain TCP segments when the affected device is operating in transparent mode. An attacker could exploit this vulnerability by sending a crafted TCP segment through an affected device. A successful exploit could allow the attacker to poison the MAC address tables in adjacent devices, resulting in network disruption.

A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Multiple vulnerabilities in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. These vulnerabilities are due to insufficient validation of CAPWAP packets. An attacker could exploit the vulnerabilities by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition.

A vulnerability in the IP Service Level Agreements (IP SLA) responder and Two-Way Active Measurement Protocol (TWAMP) features of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause device packet memory to become exhausted or cause the IP SLA process to crash, resulting in a denial of service (DoS) condition. This vulnerability exists because socket creation failures are mishandled during the IP SLA and TWAMP processes. An attacker could exploit this vulnerability by sending specific IP SLA or TWAMP packets to an affected device. A successful exploit could allow the attacker to exhaust the packet memory, which will impact other processes, such as routing protocols, or crash the IP SLA process.

A vulnerability in the DHCP message handler of Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, remote attacker to cause the supervisor to crash, which could result in a denial of service (DoS) condition. The vulnerability is due to insufficient error handling when DHCP version 4 (DHCPv4) messages are parsed. An attacker could exploit this vulnerability by sending a malicious DHCPv4 message to or through a WAN interface of an affected device. A successful exploit could allow the attacker to cause a reload of the affected device. Note: On Cisco cBR-8 Converged Broadband Routers, all of the following are considered WAN interfaces: 10 Gbps Ethernet interfaces 100 Gbps Ethernet interfaces Port channel interfaces that include multiple 10 and/or 100 Gbps Ethernet interfaces

Cisco AsyncOS on Email Security Appliance (ESA) devices with software 8.5.6-073, 8.5.6-074, and 9.0.0-461, when clustering is enabled, allows remote attackers to cause a denial of service (clustering and SSH outage) via a packet flood, aka Bug IDs CSCur13704 and CSCuq05636.

A vulnerability in the Protection Against Distributed Denial of Service Attacks feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct denial of service (DoS) attacks to or through the affected device. This vulnerability is due to incorrect programming of the half-opened connections limit, TCP SYN flood limit, or TCP SYN cookie features when the features are configured in vulnerable releases of Cisco IOS XE Software. An attacker could exploit this vulnerability by attempting to flood traffic to or through the affected device. A successful exploit could allow the attacker to initiate a DoS attack to or through an affected device.

A vulnerability in the software-based SSL/TLS message handler of Cisco Adaptive Security Appliance (ASA) Software and 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. This vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL/TLS decryption. 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 the affected device to reload, resulting in a DoS condition. Note: Datagram TLS (DTLS) messages cannot be used to exploit this vulnerability.

Cisco IOS XR 3.4.0 through 3.8.1 allows remote attackers to cause a denial of service (session reset) via a BGP UPDATE message with an invalid attribute, as demonstrated in the wild on 17 August 2009.

A vulnerability in the web-based management interface of Cisco Video Surveillance Media Server could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the web-based management interface of an affected system. The vulnerability is due to insufficient validation of user-supplied input by the web-based management interface of the affected service. An attacker could exploit this vulnerability by persuading a user of the interface to click a malicious link. A successful exploit could allow the attacker to cause the web-based management interface to become unreachable, resulting in a DoS condition.

A vulnerability in the Secure/Multipurpose Internet Mail Extensions (S/MIME) Decryption and Verification or S/MIME Public Key Harvesting features of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause an affected device to corrupt system memory. A successful exploit could cause the filtering process to unexpectedly reload, resulting in a denial of service (DoS) condition on the device. The vulnerability is due to improper input validation of S/MIME-signed emails. An attacker could exploit this vulnerability by sending a malicious S/MIME-signed email through a targeted device. If Decryption and Verification or Public Key Harvesting is configured, the filtering process could crash due to memory corruption and restart, resulting in a DoS condition. The software could then resume processing the same S/MIME-signed email, causing the filtering process to crash and restart again. A successful exploit could allow the attacker to cause a permanent DoS condition. This vulnerability may require manual intervention to recover the ESA.

A vulnerability in the email message filtering feature of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) could allow an unauthenticated, remote attacker to cause the CPU utilization to increase to 100 percent, causing a denial of service (DoS) condition on an affected device. The vulnerability is due to improper filtering of email messages that contain references to whitelisted URLs. An attacker could exploit this vulnerability by sending a malicious email message that contains a large number of whitelisted URLs. A successful exploit could allow the attacker to cause a sustained DoS condition that could force the affected device to stop scanning and forwarding email messages.

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.

A vulnerability in the AnyConnect SSL VPN 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 on an affected device. This vulnerability is due to an implementation error within the SSL/TLS session handling process that can prevent the release of a session handler under specific conditions. An attacker could exploit this vulnerability by sending crafted SSL/TLS traffic to an affected device, increasing the probability of session handler leaks. A successful exploit could allow the attacker to eventually deplete the available session handler pool, preventing new sessions from being established and causing a DoS condition.

A vulnerability in Application Quality of Experience (AppQoE) and Unified Threat Defense (UTD) on Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to the mishandling of a crafted packet stream through the AppQoE or UTD application. An attacker could exploit this vulnerability by sending a crafted packet stream through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Cisco IOS XR 5.1 allows remote attackers to cause a denial of service (DHCPv6 daemon crash) via a malformed DHCPv6 packet, aka Bug ID CSCuo59052.

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.

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 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 IPv6 subsystem of Cisco IOS XR Software Release 5.3.4 for the Cisco Aggregation Services Router (ASR) 9000 Series could allow an unauthenticated, remote attacker to trigger a reload of one or more Trident-based line cards, resulting in a denial of service (DoS) condition. The vulnerability is due to incorrect handling of IPv6 packets with a fragment header extension. An attacker could exploit this vulnerability by sending IPv6 packets designed to trigger the issue either to or through the Trident-based line card. A successful exploit could allow the attacker to trigger a reload of Trident-based line cards, resulting in a DoS during the period of time the line card takes to restart. This vulnerability affects Cisco Aggregation Services Router (ASR) 9000 Series when the following conditions are met: The router is running Cisco IOS XR Software Release 5.3.4, and the router has installed Trident-based line cards that have IPv6 configured. A software maintenance upgrade (SMU) has been made available that addresses this vulnerability. The fix has also been incorporated into service pack 7 for Cisco IOS XR Software Release 5.3.4. Cisco Bug IDs: CSCvg46800.

A vulnerability in the Bidirectional Forwarding Detection (BFD) offload implementation of Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches could allow an unauthenticated, remote attacker to cause a crash of the iosd process, causing a denial of service (DoS) condition. The vulnerability is due to insufficient error handling when the BFD header in a BFD packet is incomplete. An attacker could exploit this vulnerability by sending a crafted BFD message to or across an affected switch. A successful exploit could allow the attacker to trigger a reload of the system. This vulnerability affects Catalyst 4500 Supervisor Engine 6-E (K5), Catalyst 4500 Supervisor Engine 6L-E (K10), Catalyst 4500 Supervisor Engine 7-E (K10), Catalyst 4500 Supervisor Engine 7L-E (K10), Catalyst 4500E Supervisor Engine 8-E (K10), Catalyst 4500E Supervisor Engine 8L-E (K10), Catalyst 4500E Supervisor Engine 9-E (K10), Catalyst 4500-X Series Switches (K10), Catalyst 4900M Switch (K5), Catalyst 4948E Ethernet Switch (K5). Cisco Bug IDs: CSCvc40729.

A vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of option 82 information that it receives in DHCP Version 4 (DHCPv4) packets from DHCP relay agents. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuh91645.

The BGP implementation in Cisco NX-OS 6.2(2a) and earlier does not properly handle the interaction of UPDATE messages with IPv6, VPNv4, and VPNv6 labeled unicast-address families, which allows remote attackers to cause a denial of service (peer reset) via a crafted message, aka Bug ID CSCuj03174.

Memory leak in the connection-manager implementation in Cisco Adaptive Security Appliance (ASA) Software 9.1(.3) and earlier allows remote attackers to cause a denial of service (multi-protocol management outage) by making multiple management session requests, aka Bug ID CSCug33233.

The management implementation on Cisco ONS 15454 controller cards with software 9.8 and earlier allows remote attackers to cause a denial of service (card reset) via crafted packets, aka Bug ID CSCtz50902.