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 the Link Layer Discovery Protocol (LLDP) feature of Cisco Webex Room Phone and Cisco Webex Share devices could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient resource allocation. An attacker could exploit this vulnerability by sending crafted LLDP traffic to an affected device. A successful exploit could allow the attacker to exhaust the memory resources of the affected device, resulting in a crash of the LLDP process. If the affected device is configured to support LLDP only, this could cause an interruption to inbound and outbound calling. By default, these devices are configured to support both Cisco Discovery Protocol and LLDP. To recover operational state, the affected device needs a manual restart.

A vulnerability in the Vector Packet Processor (VPP) of Cisco Packet Data Network Gateway (PGW) could allow an unauthenticated, remote attacker to stop ICMP traffic from being processed over an IPsec connection. This vulnerability is due to the VPP improperly handling a malformed packet. An attacker could exploit this vulnerability by sending a malformed Encapsulating Security Payload (ESP) packet over an IPsec connection. A successful exploit could allow the attacker to stop ICMP traffic over an IPsec connection and cause a denial of service (DoS).

A vulnerability in the DNS inspection handler 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 condition (DoS) on an affected device. This vulnerability is due to a lack of proper processing of incoming requests. An attacker could exploit this vulnerability by sending crafted DNS requests at a high rate to an affected device. A successful exploit could allow the attacker to cause the device to stop responding, resulting in a DoS condition.

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 Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) 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 certain TLS connections that are processed by an affected device. An attacker could exploit this vulnerability by establishing a large number of concurrent TLS connections to an affected device. A successful exploit could allow the attacker to cause the device to drop new TLS email messages that come from the associated email servers. Exploitation of this vulnerability does not cause the affected device to unexpectedly reload. The device will recover autonomously within a few hours of when the attack is halted or mitigated.

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 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.

A vulnerability in the TCP state machine of Cisco RF Gateway 1 devices could allow an unauthenticated, remote attacker to prevent an affected device from delivering switched digital video (SDV) or video on demand (VoD) streams, resulting in a denial of service (DoS) condition. The vulnerability is due to a processing error with TCP connections to the affected device. An attacker could exploit this vulnerability by establishing a large number of TCP connections to an affected device and not actively closing those TCP connections. A successful exploit could allow the attacker to prevent the affected device from delivering SDV or VoD streams to set-top boxes. Cisco Bug IDs: CSCvf19887.

A vulnerability in Cisco WebEx Meetings Server could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient limitations on the number of connections that can be made to the affected software. An attacker could exploit this vulnerability by opening multiple connections to the server and exhausting server resources. A successful exploit could cause the server to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvf41006.

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 the Split DNS feature 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 occurs because the regular expression (regex) engine that is used with the Split DNS feature of affected releases may time out when it processes the DNS name list configuration. An attacker could exploit this vulnerability by trying to resolve an address or hostname that the affected device handles. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

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 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 high rate of IPv4 or IPv6 traffic through an affected device. This traffic would need to match a configured block action in an access control policy. An exploit could allow the attacker to cause a memory exhaustion condition on the affected device, which would result in a DoS for traffic transiting the device, as well as sluggish performance of the management interface. Once the flood is stopped, performance should return to previous states.

A vulnerability in the local management (local-mgmt) CLI of Cisco UCS Manager Software could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of CLI command parameters. An attacker could exploit this vulnerability by executing specific commands on the local-mgmt CLI on an affected device. A successful exploit could allow the attacker to cause internal system processes to fail to terminate properly, which could result in a buildup of stuck processes and lead to slowness in accessing the UCS Manager CLI and web UI. A sustained attack may result in a restart of internal UCS Manager processes and a temporary loss of access to the UCS Manager CLI and web UI.

A vulnerability 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 on an affected device. This vulnerability is due to insufficient resource management while establishing SSL VPN sessions. An attacker could exploit this vulnerability by sending a series of crafted HTTPS requests to the VPN server of an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to stop accepting new connections, preventing new SSL VPN connections from being established. Existing SSL VPN sessions are not impacted. Note: When the attack traffic stops, the Cisco AnyConnect VPN server recovers gracefully without requiring manual intervention.

A vulnerability in the SSH server of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition for the SSH server of an affected device. This vulnerability is due to a logic error when an SSH session is established. An attacker could exploit this vulnerability by sending crafted SSH messages to an affected device. A successful exploit could allow the attacker to exhaust available SSH resources on the affected device so that new SSH connections to the device are denied, resulting in a DoS condition. Existing SSH connections to the device would continue to function normally. The device must be rebooted manually to recover. However, user traffic would not be impacted and could be managed using a remote application such as Cisco Adaptive Security Device Manager (ASDM).

A vulnerability in system resource management in Cisco UCS 6400 and 6500 Series Fabric Interconnects that are in Intersight Managed Mode (IMM) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the Device Console UI of an affected device. This vulnerability is due to insufficient rate-limiting of TCP connections to an affected device. An attacker could exploit this vulnerability by sending a high number of TCP packets to the Device Console UI. A successful exploit could allow an attacker to cause the Device Console UI process to crash, resulting in a DoS condition. A manual reload of the fabric interconnect is needed to restore complete functionality.

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 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. This vulnerability is due to insufficient resource management when establishing TLS/SSL sessions. An attacker could exploit this vulnerability by sending a series of crafted TLS/SSL messages to the VPN server of an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to stop accepting new connections, preventing new SSL VPN connections from being established. Existing SSL VPN sessions are not impacted. Note: When the attack traffic stops, the Cisco AnyConnect VPN server recovers gracefully without requiring manual intervention.

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 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.

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.

The SSL VPN implementation in Cisco Adaptive Security Appliance (ASA) Software 9.3(.2) and earlier does not properly allocate memory blocks during HTTP packet handling, which allows remote attackers to cause a denial of service (memory consumption) via crafted packets, aka Bug ID CSCuq68888.

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

Cisco Adaptive Security Appliance (ASA) Software 8.4(.6) and earlier, when using an unsupported configuration with overlapping criteria for filtering and inspection, allows remote attackers to cause a denial of service (traffic loop and device crash) via a packet that triggers multiple matches, aka Bug ID CSCui45606.

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.

A vulnerability in the Secure Sockets Layer (SSL) packet reassembly functionality of the detection engine in Cisco Firepower System Software could allow an unauthenticated, remote attacker to cause the detection engine to consume excessive system memory on an affected device, which could cause a denial of service (DoS) condition. The vulnerability is due to the affected software improperly handling changes to SSL connection states. An attacker could exploit this vulnerability by sending crafted SSL connections through an affected device. A successful exploit could allow the attacker to cause the detection engine to consume excessive system memory on the affected device, which could cause a DoS condition. The device may need to be reloaded manually to recover from this condition. This vulnerability affects Cisco Firepower System Software Releases 6.0.0 and later, running on any of the following Cisco products: Adaptive Security Appliance (ASA) 5500-X Series Firewalls with FirePOWER Services, Adaptive Security Appliance (ASA) 5500-X Series Next-Generation Firewalls, Advanced Malware Protection (AMP) for Networks, 7000 Series Appliances, Advanced Malware Protection (AMP) for Networks, 8000 Series Appliances, Firepower 4100 Series Appliances, FirePOWER 7000 Series Appliances, FirePOWER 8000 Series Appliances, Firepower 9300 Series Security Appliances, Firepower Threat Defense for Integrated Services Routers (ISRs), Firepower Threat Defense Virtual for VMware, Industrial Security Appliance 3000, Sourcefire 3D System Appliances. Cisco Bug IDs: CSCve23031.

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.

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.

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 Decryption Policy Default Action functionality of the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass a configured drop policy and allow traffic onto the network that should have been denied. The vulnerability is due to the incorrect handling of SSL-encrypted traffic when Decrypt for End-User Notification is disabled in the configuration. An attacker could exploit this vulnerability by sending a SSL connection through the affected device. A successful exploit could allow the attacker to bypass a configured drop policy to block specific SSL connections. Releases 10.1.x and 10.5.x are affected.

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).

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 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 DHCP module 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 the affected device. The vulnerability is due to incorrect processing of certain DHCP packets. An attacker could exploit this vulnerability by sending a crafted DHCP packet to the affected device. A successful exploit could allow the attacker to cause a DoS condition on the affected device.

A vulnerability in the resource handling system of Cisco NX-OS Software for Cisco MDS 9000 Series Multilayer Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper resource usage control. An attacker could exploit this vulnerability by sending traffic to the management interface (mgmt0) of an affected device at very high rates. An exploit could allow the attacker to cause unexpected behaviors such as high CPU usage, process crashes, or even full system reboots of an affected device.

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 PROFINET feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause an affected device to crash and reload, resulting in a denial of service (DoS) condition on the device. The vulnerability is due to insufficient processing logic for crafted PROFINET packets that are sent to an affected device. An attacker could exploit this vulnerability by sending crafted PROFINET packets to an affected device for processing. A successful exploit could allow the attacker to cause the device to crash and reload, resulting in a DoS condition on the device.

A vulnerability in the packet processing of Cisco IOS XE Software for Cisco 4461 Integrated Services Routers 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 incorrect processing of IPv4 or IPv6 traffic to or through an affected device. An attacker could exploit this vulnerability by sending IP traffic to or through 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 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.