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.

Unspecified vulnerability in the Session Initiation Protocol (SIP) implementation in Cisco IOS 12.2 through 12.4 and Unified Communications Manager 4.1 through 6.1, when VoIP is configured, allows remote attackers to cause a denial of service (device or process reload) via unspecified valid SIP messages, aka Cisco Bug ID CSCsu38644, a different vulnerability than CVE-2008-3801 and CVE-2008-3802.

A vulnerability in the fragmentation handling code of tunnel protocol packets in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected system to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to the improper handling of large fragmented tunnel protocol packets. One example of a tunnel protocol is Generic Routing Encapsulation (GRE). An attacker could exploit this vulnerability by sending crafted fragmented packets to an affected system. A successful exploit could allow the attacker to cause the affected system to reload, resulting in a DoS condition. Note: Only traffic directed to the affected system can be used to exploit this vulnerability.

A vulnerability in ICMPv6 inspection when configured with the Snort 2 detection engine for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the CPU of an affected device to spike to 100 percent, which could stop all traffic processing and result in a denial of service (DoS) condition. FTD management traffic is not affected by this vulnerability. This vulnerability is due to improper error checking when parsing fields within the ICMPv6 header. An attacker could exploit this vulnerability by sending a crafted ICMPv6 packet through 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. Note: To recover from the DoS condition, the Snort 2 Detection Engine or the Cisco FTD device may need to be restarted.

Multiple vulnerabilities in the web-based user interface of certain Cisco Small Business Series Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges on an affected device. These vulnerabilities are due to improper validation of requests that are sent to the web interface. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the filesystem image parser for Hierarchical File System Plus (HFS+) of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an incorrect check for completion when a file is decompressed, which may result in a loop condition that could cause the affected software to stop responding. An attacker could exploit this vulnerability by submitting a crafted HFS+ filesystem image to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to stop responding, resulting in a DoS condition on the affected software and consuming available system resources. For a description of this vulnerability, see the ClamAV blog .

Unspecified vulnerability in the Session Initiation Protocol (SIP) implementation in Cisco IOS 12.2 through 12.4 and Unified Communications Manager 4.1 through 6.1, when VoIP is configured, allows remote attackers to cause a denial of service (device or process reload) via unspecified valid SIP messages, aka Cisco Bug ID CSCsm46064, a different vulnerability than CVE-2008-3800 and CVE-2008-3802.

Unspecified vulnerability in the Session Initiation Protocol (SIP) implementation in Cisco IOS 12.2 through 12.4, when VoIP is configured, allows remote attackers to cause a denial of service (device reload) via unspecified valid SIP messages, aka Cisco bug ID CSCsk42759, a different vulnerability than CVE-2008-3800 and CVE-2008-3801.

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.

Cisco IOS 12.4, when IOS firewall Application Inspection Control (AIC) with HTTP Deep Packet Inspection is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed HTTP transit packet.

Cisco IOS 12.0 through 12.4 on Gigabit Switch Router (GSR) devices (aka 12000 Series routers) allows remote attackers to cause a denial of service (device crash) via a malformed Protocol Independent Multicast (PIM) packet.

A vulnerability in the local Certificate Authority (CA) feature of Cisco ASA Software before 9.6(1.5) could allow an unauthenticated, remote attacker to cause a reload of the affected system. The vulnerability is due to improper handling of crafted packets during the enrollment operation. An attacker could exploit this vulnerability by sending a crafted enrollment request to the affected system. An exploit could allow the attacker to cause the reload of the affected system. Note: Only HTTPS packets directed to the Cisco ASA interface, where the local CA is allowing user enrollment, can be used to trigger this vulnerability. This vulnerability affects systems configured in routed firewall mode and in single or multiple context mode.

Memory leak in the crypto functionality in Cisco Adaptive Security Appliance (ASA) 5500 devices 7.2 before 7.2(4)2, 8.0 before 8.0(3)14, and 8.1 before 8.1(1)4, when configured as a clientless SSL VPN endpoint, allows remote attackers to cause a denial of service (memory consumption and VPN hang) via a crafted SSL or HTTP packet, aka Bug ID CSCso66472.

A vulnerability in the SSL session cache management of Cisco Wide Area Application Services (WAAS) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition due to high consumption of disk space. The user would see a performance degradation. More Information: CSCva03095. Known Affected Releases: 5.3(5), 6.1(1), 6.2(1). Known Fixed Releases: 5.3(5g)1, 6.2(2.32).

The HTTP server in Cisco Adaptive Security Appliance (ASA) 5500 devices 8.0 before 8.0(3)15 and 8.1 before 8.1(1)5, when configured as a clientless SSL VPN endpoint, does not properly process URIs, which allows remote attackers to cause a denial of service (device reload) via a URI in a crafted SSL or HTTP packet, aka Bug ID CSCsq19369.

A vulnerability in the TLS cryptography functionality of 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 improper data validation during the TLS 1.3 handshake. An attacker could exploit this vulnerability by sending a crafted TLS 1.3 packet to an affected system through a TLS 1.3-enabled listening socket. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: This vulnerability can also impact the integrity of a device by causing VPN HostScan communication failures or file transfer failures when Cisco ASA Software is upgraded using Cisco Adaptive Security Device Manager (ASDM).

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.

Cisco PIX and Adaptive Security Appliance (ASA) 5500 devices 7.2 before 7.2(4)2, 8.0 before 8.0(3)14, and 8.1 before 8.1(1)4, when configured as a client VPN endpoint, do not properly process IPSec client authentication, which allows remote attackers to cause a denial of service (device reload) via a crafted authentication attempt, aka Bug ID CSCso69942.

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.

A vulnerability in the Remote Access VPN feature of 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 on an affected device. This vulnerability is due to improper validation of client key data after the TLS session is established. An attacker could exploit this vulnerability by sending a crafted key value to an affected system over the secure TLS session. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Cisco IOS 12.2 through 12.4 and 15.0 through 15.6 and IOS XE 3.1 through 3.17 and 16.2 allow remote attackers to cause a denial of service (device reload) via crafted fields in an H.323 message, aka Bug ID CSCux04257.

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 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.

A vulnerability in the multicast traceroute version 2 (Mtrace2) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust the UDP packet memory of an affected device. This vulnerability exists because the Mtrace2 code does not properly handle packet memory. An attacker could exploit this vulnerability by sending crafted packets to an affected device. A successful exploit could allow the attacker to exhaust the incoming UDP packet memory. The affected device would not be able to process higher-level UDP-based protocols packets, possibly causing a denial of service (DoS) condition. Note: This vulnerability can be exploited using IPv4 or IPv6.

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 Protocol Independent Multicast (PIM) feature of Cisco IOS XE 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 received IPv4 PIMv2 packets. An attacker could exploit this vulnerability by sending a crafted PIMv2 packet to a PIM-enabled interface on an affected device. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition. Note: This vulnerability can be exploited with either an IPv4 multicast or unicast packet.

Multiple vulnerabilities in the web-based management interface of Cisco Small Business SPA300 Series IP Phones and Cisco Small Business SPA500 Series IP Phones could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly. These vulnerabilities exist because HTTP packets are not properly checked for errors. An attacker could exploit this vulnerability by sending a crafted HTTP packet to the remote interface of an affected device. A successful exploit could allow the attacker to cause a DoS condition on the device.

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 implementation of the IPv4 fragmentation reassembly code in Cisco IOS XE 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 management of resources during fragment reassembly. An attacker could exploit this vulnerability by sending specific sizes of fragmented packets to an affected device or through a Virtual Fragmentation Reassembly (VFR)-enabled interface on an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: This vulnerability affects Cisco ASR 1000 Series Aggregation Services Routers and Cisco cBR-8 Converged Broadband Routers if they are running Cisco IOS XE Software Release 17.12.1 or 17.12.1a.

Cisco IOS 12.4 and 15.0 through 15.6 and IOS XE 3.1 through 3.18 and 16.1 allow remote attackers to cause a denial of service (memory consumption or device reload) via fragmented IKEv1 packets, aka Bug ID CSCuy47382.

The AAA service in Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 2.1 through 3.18 and 16.2 allows remote attackers to cause a denial of service (device reload) via a failed SSH connection attempt that is mishandled during generation of an error-log message, aka Bug ID CSCuy87667.

Memory leak in the virtual private dial-up network (VPDN) component in Cisco IOS before 12.3 allows remote attackers to cause a denial of service (memory consumption) via a series of PPTP sessions, related to "dead memory" that remains allocated after process termination, aka bug ID CSCsj58566.

The virtual private dial-up network (VPDN) component in Cisco IOS before 12.3 allows remote attackers to cause a denial of service (resource exhaustion) via a series of PPTP sessions, related to the persistence of interface descriptor block (IDB) data structures after process termination, aka bug ID CSCdv59309.

A vulnerability with the Border Gateway Protocol (BGP) for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a routing process to crash, which could lead to a denial of service (DoS) condition. This vulnerability is due to an issue with the installation of routes upon receipt of a BGP update. An attacker could exploit this vulnerability by sending a crafted BGP update to an affected device. A successful exploit could allow the attacker to cause the routing process to crash, which could cause the device to reload. This vulnerability applies to both Internal BGP (IBGP) and External BGP (EBGP). Note: The Cisco implementation of BGP accepts incoming BGP traffic from explicitly configured peers only. To exploit this vulnerability, an attacker would need to send a specific BGP update message over an established TCP connection that appears to come from a trusted BGP peer.

Unspecified vulnerability in the Supervisor Engine 32 (Sup32), Supervisor Engine 720 (Sup720), and Route Switch Processor 720 (RSP720) for multiple Cisco products, when using Multi Protocol Label Switching (MPLS) VPN and OSPF sham-link, allows remote attackers to cause a denial of service (blocked queue, device restart, or memory leak) via unknown vectors.

Unspecified vulnerability in Cisco PIX 500 Series Security Appliance and 5500 Series Adaptive Security Appliance (ASA) before 7.2(3)6 and 8.0(3), when the Time-to-Live (TTL) decrement feature is enabled, allows remote attackers to cause a denial of service (device reload) via a crafted IP packet.

A vulnerability in the HTTPS decryption feature of Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient validation of Secure Sockets Layer (SSL) server certificates. An attacker could exploit this vulnerability by installing a malformed certificate in a web server and sending a request to it through the Cisco WSA. A successful exploit could allow the attacker to cause an unexpected restart of the proxy process on an affected device.

Multiple vulnerabilities in Cisco SD-WAN products could allow an unauthenticated, remote attacker to execute denial of service (DoS) attacks against an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

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 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 Multi-Pod or Multi-Site network configurations for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to unexpectedly restart the device, resulting in a denial of service (DoS) condition. This vulnerability exists because TCP traffic sent to a specific port on an affected device is not properly sanitized. An attacker could exploit this vulnerability by sending crafted TCP data to a specific port that is listening on a public-facing IP address for the Multi-Pod or Multi-Site configuration. A successful exploit could allow the attacker to cause the device to restart unexpectedly, resulting in a DoS condition.