A vulnerability in the Link Layer Discovery Protocol (LLDP) message parser of Cisco IOS Software and Cisco IOS XE Software could allow an attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to improper initialization of a buffer. An attacker could exploit this vulnerability via any of the following methods: An authenticated, remote attacker could access the LLDP neighbor table via either the CLI or SNMP while the device is in a specific state. An unauthenticated, adjacent attacker could corrupt the LLDP neighbor table by injecting specific LLDP frames into the network and then waiting for an administrator of the device or a network management system (NMS) managing the device to retrieve the LLDP neighbor table of the device via either the CLI or SNMP. An authenticated, adjacent attacker with SNMP read-only credentials or low privileges on the device CLI could corrupt the LLDP neighbor table by injecting specific LLDP frames into the network and then accessing the LLDP neighbor table via either the CLI or SNMP. A successful exploit could allow the attacker to cause the affected device to crash, resulting in a reload of the device.

Cisco IOS before 12.3-7-JA2 on Aironet Wireless Access Points (WAP) allows remote authenticated users to cause a denial of service (termination of packet passing or termination of client connections) by sending the management interface a large number of spoofed ARP packets, which creates a large ARP table that exhausts memory, aka Bug ID CSCsc16644.

A vulnerability in the implementation of Extensible Authentication Protocol over LAN (EAPOL) functionality in Cisco Small Business 100 Series Wireless Access Points and Cisco Small Business 300 Series Wireless Access Points could allow an authenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper processing of certain EAPOL frames. An attacker could exploit this vulnerability by sending a stream of crafted EAPOL frames to an affected device. A successful exploit could allow the attacker to force the access point (AP) to disassociate all the associated stations (STAs) and to disallow future, new association requests. Cisco Bug IDs: CSCvj97472.

A vulnerability in the quality of service (QoS) feature of Cisco Aironet Series Access Points (APs) could allow an authenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper input validation on QoS fields within Wi-Fi frames by the affected device. An attacker could exploit this vulnerability by sending malformed Wi-Fi frames to an affected device. A successful exploit could allow the attacker to cause the affected device to crash, resulting in a DoS condition.

A vulnerability in the web-based management interface of Cisco IC3000 Industrial Compute Gateway could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability exists because the affected software improperly manages system resources. An attacker could exploit this vulnerability by opening a large number of simultaneous sessions on the web-based management interface of an affected device. A successful exploit could allow the attacker to cause a DoS condition of the web-based management interface, preventing normal management operations.

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 trigger a reload of an affected device, resulting in 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. The attacker does not need valid credentials to authenticate the VPN session, nor does the attacker's source address need to match a peer statement in the crypto map applied to the ingress interface of the affected device. An exploit could allow the attacker to exhaust system memory resources, leading to a reload of an affected device.

A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol implementation of Cisco Aironet and Catalyst 9100 Access Points (APs) could allow an unauthenticated, adjacent attacker to cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to improper resource management during CAPWAP message processing. An attacker could exploit this vulnerability by sending a high volume of legitimate wireless management frames within a short time to an affected device. A successful exploit could allow the attacker to cause a device to restart unexpectedly, resulting in a DoS condition for clients associated with the AP.

A vulnerability in the memory management of Cisco Adaptive Security Appliance (ASA) Software and 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 resource management when connection rates are high. An attacker could exploit this vulnerability by opening a significant number of connections on an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.

A vulnerability in the filesystem resource management code of Cisco IOS XE Software could allow an unauthenticated, remote attacker to exhaust filesystem resources on an affected device and cause a denial of service (DoS) condition. The vulnerability is due to ineffective management of the underlying filesystem resources. An attacker could exploit this vulnerability by performing specific actions that result in messages being sent to specific operating system log files. A successful exploit could allow the attacker to exhaust available filesystem space on an affected device. This could cause the device to crash and reload, resulting in a DoS condition for clients whose network traffic is transiting the device. Upon reload of the device, the impacted filesystem space is cleared, and the device will return to normal operation. However, continued exploitation of this vulnerability could cause subsequent forced crashes and reloads, which could lead to an extended DoS condition.

A vulnerability in the WebVPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause increased CPU utilization on an affected device. The vulnerability is due to excessive processing load for a specific WebVPN HTTP page request. An attacker could exploit this vulnerability by sending multiple WebVPN HTTP page load requests for a specific URL. A successful exploit could allow the attacker to increase CPU load on the device, resulting in a denial of service (DoS) condition, which could cause traffic to be delayed through the device.

A vulnerability in the configuration of the Pluggable Authentication Module (PAM) used in Cisco Firepower Threat Defense (FTD) Software, Cisco Firepower Management Center (FMC) Software, and Cisco FXOS Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper resource management in the context of user session management. An attacker could exploit this vulnerability by connecting to an affected system and performing many simultaneous successful Secure Shell (SSH) logins. A successful exploit could allow the attacker to exhaust system resources and cause the device to reload, resulting in a DoS condition. To exploit this vulnerability, the attacker needs valid user credentials on the system.

A vulnerability in the HTTP server code of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the HTTP server to crash. The vulnerability is due to a logical error in the logging mechanism. An attacker could exploit this vulnerability by generating a high amount of long-lived connections to the HTTP service on the device. A successful exploit could allow the attacker to cause the HTTP server to crash.

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to trigger a denial of service (DoS) condition on an affected device. This vulnerability is due to improper control of a resource. An attacker with the ability to spoof a trusted IKEv2 site-to-site VPN peer and in possession of valid IKEv2 credentials for that peer could exploit this vulnerability by sending malformed, authenticated IKEv2 messages to an affected device. A successful exploit could allow the attacker to trigger a reload of the device.

A vulnerability in SSL/TLS message handler for 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 exists because incoming SSL/TLS packets are not properly processed. An attacker could exploit this vulnerability by sending a crafted SSL/TLS packet 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 detection engine reassembly of Secure Sockets Layer (SSL) packets for Cisco Firepower System Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition because the Snort process consumes a high level of CPU resources. Affected Products: This vulnerability affects Cisco Firepower System Software running software releases 6.0.0, 6.1.0, 6.2.0, or 6.2.1 when the device is configured with an SSL policy that has at least one rule specifying traffic decryption. More Information: CSCvc58563. Known Affected Releases: 6.0.0 6.1.0 6.2.0 6.2.1.

A vulnerability in the SSH service of the Cisco StarOS operating system could allow an unauthenticated, remote attacker to cause an affected device to stop processing traffic, resulting in a denial of service (DoS) condition. The vulnerability is due to a logic error that may occur under specific traffic conditions. An attacker could exploit this vulnerability by sending a series of crafted packets to an affected device. A successful exploit could allow the attacker to prevent the targeted service from receiving any traffic, which would lead to a DoS condition on the affected device.

Multiple vulnerabilities in the implementation of the Cisco Discovery Protocol and Link Layer Discovery Protocol (LLDP) for Cisco Video Surveillance 7000 Series IP Cameras could allow an unauthenticated, adjacent attacker to cause a memory leak, which could lead to a denial of service (DoS) condition on an affected device. These vulnerabilities are due to incorrect processing of certain Cisco Discovery Protocol and LLDP packets at ingress time. An attacker could exploit these vulnerabilities by sending crafted Cisco Discovery Protocol or LLDP packets to an affected device. A successful exploit could allow the attacker to cause the affected device to continuously consume memory, which could cause the device to crash and reload, resulting in a DoS condition. Note: Cisco Discovery Protocol and LLDP are Layer 2 protocols. To exploit these vulnerabilities, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

Multiple vulnerabilities in Cisco SD-WAN vManage Software could allow an unauthenticated, remote attacker to execute arbitrary code or gain access to sensitive information, or allow an authenticated, local attacker to gain escalated privileges or gain unauthorized access to the application. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the REST API of Cisco Managed Services Accelerator (MSX) could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the way that the affected software logs certain API requests. An attacker could exploit this vulnerability by sending a flood of crafted API requests to an affected device. A successful exploit could allow the attacker to cause a DoS condition on the affected device.

A vulnerability in the Cisco IOx Application Framework of Cisco 809 Industrial Integrated Services Routers (Industrial ISRs), Cisco 829 Industrial ISRs, Cisco CGR 1000 Compute Module, and Cisco IC3000 Industrial Compute Gateway could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient error handling during packet processing. An attacker could exploit this vulnerability by sending a high and sustained rate of crafted TCP traffic to the IOx web server on an affected device. A successful exploit could allow the attacker to cause the IOx web server to stop processing requests, resulting in a DoS condition.

Multiple vulnerabilities in the implementation of the Cisco Discovery Protocol and Link Layer Discovery Protocol (LLDP) for Cisco Video Surveillance 7000 Series IP Cameras could allow an unauthenticated, adjacent attacker to cause a memory leak, which could lead to a denial of service (DoS) condition on an affected device. These vulnerabilities are due to incorrect processing of certain Cisco Discovery Protocol and LLDP packets at ingress time. An attacker could exploit these vulnerabilities by sending crafted Cisco Discovery Protocol or LLDP packets to an affected device. A successful exploit could allow the attacker to cause the affected device to continuously consume memory, which could cause the device to crash and reload, resulting in a DoS condition. Note: Cisco Discovery Protocol and LLDP are Layer 2 protocols. To exploit these vulnerabilities, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

A vulnerability in the system resource management of Cisco Elastic Services Controller (ESC) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) to the health monitor API on an affected device. The vulnerability is due to inadequate provisioning of kernel parameters for the maximum number of TCP connections and SYN backlog. An attacker could exploit this vulnerability by sending a flood of crafted TCP packets to an affected device. A successful exploit could allow the attacker to block TCP listening ports that are used by the health monitor API. This vulnerability only affects customers who use the health monitor API.

A vulnerability in the Common Open Policy Service (COPS) of Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, remote attacker to cause resource exhaustion, resulting in a denial of service (DoS) condition. This vulnerability is due to a deadlock condition in the code when processing COPS packets under certain conditions. An attacker could exploit this vulnerability by sending COPS packets with high burst rates to an affected device. A successful exploit could allow the attacker to cause the CPU to consume excessive resources, which prevents other control plane processes from obtaining resources and results in a DoS.

A vulnerability in filesystem usage management for Cisco Firepower Device Manager (FDM) Software could allow an authenticated, remote attacker to exhaust filesystem resources, resulting in a denial of service (DoS) condition on an affected device. This vulnerability is due to the insufficient management of available filesystem resources. An attacker could exploit this vulnerability by uploading files to the device and exhausting available filesystem resources. A successful exploit could allow the attacker to cause database errors and cause the device to become unresponsive to web-based management. Manual intervention is required to free filesystem resources and return the device to an operational state.

A vulnerability in the ingress flow creation functionality of Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to cause the CPU to increase upwards of 100% utilization, causing a denial of service (DoS) condition on an affected system. The vulnerability is due to incorrect handling of an internal software lock that could prevent other system processes from getting CPU cycles, causing a high CPU condition. An attacker could exploit this vulnerability by sending a steady stream of malicious IP packets that can cause connections to be created on the targeted device. A successful exploit could allow the attacker to exhaust CPU resources, resulting in a DoS condition during which traffic through the device could be delayed. This vulnerability applies to either IPv4 or IPv6 ingress traffic. This vulnerability affects Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software that is running on the following Cisco products: 3000 Series Industrial Security Appliances (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 Appliances (ASAv), Firepower 2100 Series Security Appliances, Firepower 4110 Security Appliances, Firepower 9300 ASA Security Modules. Cisco Bug IDs: CSCvf63718.

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.

Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service.

A vulnerability in the DHCP snooping security feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a full interface queue wedge, which could result in a denial of service (DoS) condition. This vulnerability is due to improper handling of DHCP request packets. An attacker could exploit this vulnerability by sending DHCP request packets to an affected device. A successful exploit could allow the attacker to cause packets to wedge in the queue, creating a DoS condition for downstream devices of the affected system and requiring that the system restart to drain the queue. Note: This vulnerability can be exploited with either unicast or broadcast DHCP packets on a VLAN that does not have DHCP snooping enabled.

A vulnerability in the Address Resolution Protocol (ARP) implementation of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to trigger a broadcast storm, leading to a denial of service (DoS) condition on an affected device.  This vulnerability is due to how Cisco IOS XR Software processes a high, sustained rate of ARP traffic hitting the management interface. Under certain conditions, an attacker could exploit this vulnerability by sending an excessive amount of traffic to the management interface of an affected device, overwhelming its ARP processing capabilities. A successful exploit could result in degraded device performance, loss of management connectivity, and complete unresponsiveness of the system, leading to a DoS condition.

A vulnerability in the SSH service of Cisco IEC6400 Wireless Backhaul Edge Compute Software could allow an unauthenticated, remote attacker to cause the SSH service to stop responding. This vulnerability exists because the SSH service lacks effective flood protection. An attacker could exploit this vulnerability by initiating a denial of service (DoS) attack against the SSH port. A successful exploit could allow the attacker to cause the SSH service to be unresponsive during the period of the DoS attack. All other operations remain stable during the attack.

A vulnerability in the system scanning component of Cisco Immunet and Cisco Advanced Malware Protection (AMP) for Endpoints running on Microsoft Windows could allow a local attacker to disable the scanning functionality of the product. This could allow executable files to be launched on the system without being analyzed for threats. The vulnerability is due to improper process resource handling. An attacker could exploit this vulnerability by gaining local access to a system running Microsoft Windows and protected by Cisco Immunet or Cisco AMP for Endpoints and executing a malicious file. A successful exploit could allow the attacker to prevent the scanning services from functioning properly and ultimately prevent the system from being protected from further intrusion.

A vulnerability in the WebVPN login process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause increased CPU utilization on an affected device. The vulnerability is due to excessive processing load for existing WebVPN login operations. An attacker could exploit this vulnerability by sending multiple WebVPN login requests to the device. A successful exploit could allow the attacker to increase CPU load on the device, resulting in a denial of service (DoS) condition.

A vulnerability in the Cisco Network Plug and Play agent, also referred to as the Cisco Open Plug-n-Play agent, of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak on an affected device. The vulnerability is due to insufficient input validation by the affected software. An attacker could exploit this vulnerability by sending invalid data to the Cisco Network Plug and Play agent on an affected device. A successful exploit could allow the attacker to cause a memory leak on the affected device, which could cause the device to reload.

A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to bypass a configured Intrusion Prevention System (IPS) rule that inspects certain types of TCP traffic. The vulnerability is due to incorrect TCP retransmission handling. An attacker could exploit this vulnerability by sending a crafted TCP connection request through an affected device. A successful exploit could allow the attacker to bypass configured IPS rules and allow uninspected traffic onto the network.

A vulnerability in the Bulk Administration Tool (BAT) for Cisco Unity Connection could allow an authenticated, remote attacker to cause high disk utilization, resulting in a denial of service (DoS) condition. The vulnerability exists because the affected software does not restrict the maximum size of certain files that can be written to disk. An attacker who has valid administrator credentials for an affected system could exploit this vulnerability by sending a crafted, remote connection request to an affected system. A successful exploit could allow the attacker to write a file that consumes most of the available disk space on the system, causing application functions to operate abnormally and leading to a DoS condition.

A vulnerability in Cisco 900 Series Aggregation Services Router (ASR) software could allow an unauthenticated, remote attacker to cause a partial denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient handling of certain broadcast packets ingress to the device. An attacker could exploit this vulnerability by sending large streams of broadcast packets to an affected device. If successful, an exploit could allow an attacker to impact services running on the device, resulting in a partial DoS condition.

A vulnerability in the TCP syslog module of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust the 1550-byte buffers on an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a missing boundary check in an internal function. An attacker could exploit this vulnerability by establishing a man-in-the-middle position between an affected device and its configured TCP syslog server and then maliciously modifying the TCP header in segments that are sent from the syslog server to the affected device. A successful exploit could allow the attacker to exhaust buffer on the affected device and cause all TCP-based features to stop functioning, resulting in a DoS condition. The affected TCP-based features include AnyConnect SSL VPN, clientless SSL VPN, and management connections such as Secure Shell (SSH), Telnet, and HTTPS.

A vulnerability in the cryptographic hardware accelerator driver 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 temporary denial of service (DoS) condition. The vulnerability exists because the affected devices have a limited amount of Direct Memory Access (DMA) memory and the affected software improperly handles resources in low-memory conditions. An attacker could exploit this vulnerability by sending a sustained, high rate of malicious traffic to an affected device to exhaust memory on the device. A successful exploit could allow the attacker to exhaust DMA memory on the affected device, which could cause the device to reload and result in a temporary DoS condition.

The Intercluster Sync Agent Service in Cisco Unified Presence Server allows remote attackers to cause a denial of service via a TCP SYN flood, aka Bug ID CSCun34125.

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.

A vulnerability in the packet processing functionality of Cisco access point (AP) software could allow an unauthenticated, adjacent attacker to exhaust resources on an affected device.  This vulnerability is due to insufficient management of resources when handling certain types of traffic. An attacker could exploit this vulnerability by sending a series of specific wireless packets to an affected device. A successful exploit could allow the attacker to consume resources on an affected device. A sustained attack could lead to the disruption of the Control and Provisioning of Wireless Access Points (CAPWAP) tunnel and intermittent loss of wireless client traffic.

A vulnerability in an API endpoint of multiple Cisco Unified Communications Products could allow an unauthenticated, remote attacker to cause high CPU utilization, which could impact access to the web-based management interface and cause delays with call processing. This API is not used for device management and is unlikely to be used in normal operations of the device. This vulnerability is due to improper API authentication and incomplete validation of the API request. An attacker could exploit this vulnerability by sending a crafted HTTP request to a specific API on the device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition due to high CPU utilization, which could negatively impact user traffic and management access. When the attack stops, the device will recover without manual intervention.

A vulnerability in the networking component of Cisco access point (AP) software could allow an unauthenticated, remote attacker to cause a temporary disruption of service. This vulnerability is due to overuse of AP resources. An attacker could exploit this vulnerability by connecting to an AP on an affected device as a wireless client and sending a high rate of traffic over an extended period of time. A successful exploit could allow the attacker to cause the Datagram TLS (DTLS) session to tear down and reset, causing a denial of service (DoS) condition.