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 management and VPN web servers of the Remote Access SSL VPN feature of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to unexpectedly stop responding, resulting in a DoS condition. This vulnerability is due to ineffective validation of user-supplied input during the Remote Access SSL VPN authentication process. An attacker could exploit this vulnerability by sending a crafted request to the VPN service on an affected device. A successful exploit could allow the attacker to cause a DoS condition where the device stops responding to Remote Access SSL VPN authentication requests.

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) feature of Cisco IOS Software, IOS XE Software, Secure Firewall Adaptive Security Appliance (ASA) Software, and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition. This vulnerability is due to a lack of proper processing of IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. In the case of Cisco IOS and IOS XE Software, a successful exploit could allow the attacker to cause the device to reload unexpectedly. In the case of Cisco ASA and FTD Software, a successful exploit could allow the attacker to partially exhaust system memory, causing system instability such as being unable to establish new IKEv2 VPN sessions. A manual reboot of the device is required to recover from this condition.

The ethernet-lldp component in Cisco IOS 12.2 before 12.2(33)SXJ1 does not properly support a large number of LLDP Management Address (MA) TLVs, which allows remote attackers to cause a denial of service (device crash) via crafted LLDPDUs, aka Bug ID CSCtj22354.

A vulnerability in the local interface of Cisco BroadWorks Network Server could allow an unauthenticated, remote attacker to exhaust system resources, causing a denial of service (DoS) condition. This vulnerability exists because rate limiting does not occur for certain incoming TCP connections. An attacker could exploit this vulnerability by sending a high rate of TCP connections to the server. A successful exploit could allow the attacker to cause TCP connection resources to grow rapidly until the Cisco BroadWorks Network Server becomes unusable. Note: To recover from this vulnerability, either Cisco BroadWorks Network Server software must be restarted or the Cisco BroadWorks Network Server node must be rebooted. For more information, see the section of this advisory. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

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.

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.

CallManager Express (CME) on Cisco IOS before 15.0(1)XA1 does not properly handle SIP TRUNK traffic that contains rate bursts and a "peculiar" request size, which allows remote attackers to cause a denial of service (memory consumption) by sending this traffic over a long duration, aka Bug ID CSCtb47950.

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.

Multiple Cisco products are affected by a vulnerability in the way the Snort detection engine processes ICMP traffic that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper memory resource management while the Snort detection engine is processing ICMP packets. An attacker could exploit this vulnerability by sending a series of ICMP packets through an affected device. A successful exploit could allow the attacker to exhaust resources on the affected device, causing the device to reload.

The Multicast Source Discovery Protocol (MSDP) implementation in Cisco IOS 12.0, 12.2 through 12.4, and 15.0 through 15.2 and IOS XE 2.1.x through 2.6.x and 3.1.xS through 3.4.xS before 3.4.1S and 3.1.xSG and 3.2.xSG before 3.2.2SG allows remote attackers to cause a denial of service (device reload) via encapsulated IGMP data in an MSDP packet, aka Bug ID CSCtr28857.

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.

A vulnerability in the proxy service of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to exhaust system memory and cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper memory management in the proxy service of an affected device. An attacker could exploit this vulnerability by establishing a large number of HTTPS connections to the affected device. A successful exploit could allow the attacker to cause the system to stop processing new connections, which could result in a DoS condition. Note: Manual intervention may be required to recover from this situation.

A vulnerability in the Network Time Protocol (NTP) feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to excessive use of system resources when the affected device is logging a drop action for received MODE_PRIVATE (Mode 7) NTP packets. An attacker could exploit this vulnerability by flooding the device with a steady stream of Mode 7 NTP packets. A successful exploit could allow the attacker to cause high CPU and memory usage on the affected device, which could cause internal system processes to restart or cause the affected device to unexpectedly reload. Note: The NTP feature is enabled by default.

A vulnerability in the interactions between the DHCP and TFTP features for Cisco Small Business 300 Series (Sx300) Managed Switches could allow an unauthenticated, remote attacker to cause the device to become low on system memory, which in turn could lead to an unexpected reload of the device and result in a denial of service (DoS) condition on an affected device. The vulnerability is due to a failure to free system memory when an unexpected DHCP request is received. An attacker could exploit this vulnerability by sending a crafted DHCP packet to the targeted device. A successful exploit could allow the attacker to cause an unexpected reload of the device.

A vulnerability in the internal packet-processing functionality of Cisco Firepower Threat Defense (FTD) Software for the Cisco Firepower 2100 Series 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, which may prevent ingress buffers from being replenished 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 consume all input buffers, which are shared between all interfaces, leading to a queue wedge condition in all active interfaces. This situation would cause an affected device to stop processing any incoming traffic and result in a DoS condition until the device is reloaded manually.

A vulnerability in the processing of IP Service Level Agreement (SLA) packets by Cisco IOS Software and Cisco IOS XE software could allow an unauthenticated, remote attacker to cause an interface wedge and an eventual denial of service (DoS) condition on the affected device. The vulnerability is due to improper socket resources handling in the IP SLA responder application code. An attacker could exploit this vulnerability by sending crafted IP SLA packets to an affected device. An exploit could allow the attacker to cause an interface to become wedged, resulting in an eventual denial of service (DoS) condition on the affected device.

A vulnerability in the Cisco Fabric Services over IP (CFSoIP) feature 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 insufficient validation of incoming CFSoIP packets. An attacker could exploit this vulnerability by sending crafted CFSoIP packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

On April 20, 2022, the following vulnerability in the ClamAV scanning library versions 0.103.5 and earlier and 0.104.2 and earlier was disclosed: A vulnerability in HTML file parser of Clam AntiVirus (ClamAV) versions 0.104.0 through 0.104.2 and LTS version 0.103.5 and prior versions could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. For a description of this vulnerability, see the ClamAV blog. This advisory will be updated as additional information becomes available.

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

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

A vulnerability in the Internet Key Exchange Version 2 Mobility and Multihoming Protocol (MOBIKE) feature for the Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a memory leak or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to the incorrect processing of certain MOBIKE packets. An attacker could exploit this vulnerability by sending crafted MOBIKE packets to an affected device to be processed. A successful exploit could cause an affected device to continuously consume memory and eventually reload, resulting in a DoS condition. The MOBIKE feature is supported only for IPv4 addresses.

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.

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 IPv4 protocol handling of Cisco StarOS could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory leak that occurs during packet processing. An attacker could exploit this vulnerability by sending a series of crafted IPv4 packets through an affected device. A successful exploit could allow the attacker to exhaust the available memory and cause an unexpected restart of the npusim process, leading to a DoS condition on the affected device.

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.

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 Umbrella Connector component of Cisco IOS XE Software for Cisco Catalyst 9200 Series Switches could allow an unauthenticated, remote attacker to trigger a reload, resulting in a denial of service condition on an affected device. The vulnerability is due to insufficient error handling when parsing DNS requests. An attacker could exploit this vulnerability by sending a series of malicious DNS requests to an Umbrella Connector client interface of an affected device. A successful exploit could allow the attacker to cause a crash of the iosd process, which triggers a reload of the affected device.

A vulnerability in the TCP packet processing of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a memory exhaustion condition. An attacker could exploit this vulnerability by sending a high rate of crafted TCP traffic through an affected device. A successful exploit could allow the attacker to exhaust device resources, resulting in a DoS condition for traffic transiting the affected device.

Multiple vulnerabilities in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to either immediately crash the Internet Group Management Protocol (IGMP) process or make it consume available memory and eventually crash. The memory consumption may negatively impact other processes that are running on the device. These vulnerabilities are due to the incorrect handling of IGMP packets. An attacker could exploit these vulnerabilities by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to immediately crash the IGMP process or cause memory exhaustion, resulting in other processes becoming unstable. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address these vulnerabilities.

A vulnerability in the Polaris kernel of Cisco Catalyst 9200 Series Switches could allow an unauthenticated, remote attacker to crash the device. The vulnerability is due to insufficient packet size validation. An attacker could exploit this vulnerability by sending jumbo frames or frames larger than the configured MTU size to the management interface of this device. A successful exploit could allow the attacker to crash the device fully before an automatic recovery.

A vulnerability in Cisco Aironet Access Points (APs) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) on an affected device. The vulnerability is due to improper resource management while processing specific packets. An attacker could exploit this vulnerability by sending a series of crafted UDP packets to a specific port on an affected device. A successful exploit could either allow the attacker to tear down the connection between the AP and the wireless LAN controller, resulting in the affected device not being able to process client traffic, or cause the vulnerable device to reload, triggering a DoS condition. After the attack, the affected device should automatically recover its normal functions without manual intervention.

A vulnerability in the packet processing functionality of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to inefficient memory management. An attacker could exploit this vulnerability by sending a large number of TCP packets to a specific port on an affected device. A successful exploit could allow the attacker to exhaust system memory, which could cause the device to reload unexpectedly. No manual intervention is needed to recover the device after it has reloaded.

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

A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust process memory of an affected device. The vulnerability is due to insufficient queue management for Internet Group Management Protocol (IGMP) packets. An attacker could exploit this vulnerability by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to cause memory exhaustion, resulting in instability of other processes. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address this vulnerability.

A vulnerability in the ICMP ingress packet processing of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 4110 appliances could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to incomplete input validation upon receiving ICMP packets. An attacker could exploit this vulnerability by sending a high number of crafted ICMP or ICMPv6 packets to an affected device. A successful exploit could allow the attacker to cause a memory exhaustion condition that may result in an unexpected reload. No manual intervention is needed to recover the device after the reload.

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

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

A vulnerability in the implementation of Multiprotocol Border Gateway Protocol (MP-BGP) for the Layer 2 VPN (L2VPN) Ethernet VPN (EVPN) address family in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to incorrect processing of Border Gateway Protocol (BGP) update messages that contain crafted EVPN attributes. An attacker could exploit this vulnerability by sending BGP update messages with specific, malformed attributes to an affected device. A successful exploit could allow the attacker to cause an affected device to crash, resulting in a DoS condition.

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

A vulnerability in Cisco Aironet Access Point (AP) Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to improper handling of clients that are trying to connect to the AP. An attacker could exploit this vulnerability by sending authentication requests from multiple clients to an affected device. A successful exploit could allow the attacker to cause the affected device to reload.

A vulnerability in the locally significant certificate (LSC) provisioning feature of Cisco Catalyst 9800 Series Wireless Controllers that are running Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak that could lead to a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain public key infrastructure (PKI) packets. An attacker could exploit this vulnerability by sending crafted Secure Sockets Layer (SSL) packets to an affected device. A successful exploit could cause an affected device to continuously consume memory, which could result in a memory allocation failure that leads to a crash and causes a DoS condition.