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.

The cat6000-dot1x component in Cisco IOS 12.2 before 12.2(33)SXI7 does not properly handle an external loop between a pair of dot1x enabled ports, which allows remote attackers to cause a denial of service (traffic storm) via unspecified vectors that trigger many unicast EAPoL Protocol Data Units (PDUs), aka Bug ID CSCtq36336.

The do_change_cipher_spec function in OpenSSL 0.9.6c to 0.9.6k, and 0.9.7a to 0.9.7c, allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that triggers a null dereference.

Cisco IOS before 15.0(1)XA1, when certain TFTP debugging is enabled, allows remote attackers to cause a denial of service (device crash) via a TFTP copy over IPv6, aka Bug ID CSCtb28877.

Buffer overflow in the embedded HTTP server for Cisco Catalyst switches running CatOS 5.4 through 7.3 allows remote attackers to cause a denial of service (reset) via a long HTTP request.

Unspecified vulnerability on the Cisco Firewall Services Module (FWSM) with software 3.2 before 3.2(17.2), 4.0 before 4.0(11.1), and 4.1 before 4.1(1.2) for Catalyst 6500 series switches and 7600 series routers, when multi-mode is enabled, allows remote attackers to cause a denial of service (device reload) via crafted (1) Telnet, (2) SSH, or (3) ASDM traffic over TCP, aka Bug ID CSCtg68694.

Cisco IOS 12.0 through 12.2, when supporting SSH, allows remote attackers to cause a denial of service (CPU consumption) via a large packet that was designed to exploit the SSH CRC32 attack detection overflow (CVE-2001-0144).

The IGMPv3 implementation in Cisco IOS 12.2, 12.3, 12.4, and 15.0 and IOS XE 2.5.x before 2.5.2, when PIM is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed IGMP packet, aka Bug ID CSCte14603.

Cisco Unified Personal Communicator 7.0 (1.13056) does not free allocated memory for received data and does not perform validation if memory allocation is successful, causing a remote denial of service condition.

Cisco IOS XR 3.4.0 through 3.9.1, when BGP is enabled, does not properly handle unrecognized transitive attributes, which allows remote attackers to cause a denial of service (peering reset) via a crafted prefix announcement, as demonstrated in the wild in August 2010 with attribute type code 99, aka Bug ID CSCti62211.

Multiple unspecified vulnerabilities in the (1) Mobile IP NAT Traversal feature and (2) Mobile IPv6 subsystem in Cisco IOS 12.3 through 12.4 allow remote attackers to cause a denial of service (input queue wedge and interface outage) via MIPv6 packets, aka Bug ID CSCsm97220.

Heap-based buffer overflow in the TFTP server capability in Cisco IOS 11.1, 11.2, and 11.3 allows remote attackers to cause a denial of service (reset) or modify configuration via a long filename.

Cisco IOS 12.2 through 12.4, when certain PMTUD, SNAT, or window-size configurations are used, allows remote attackers to cause a denial of service (infinite loop, and device reload or hang) via a TCP segment with crafted options, aka Bug ID CSCsz75186.

Unspecified vulnerability in Cisco ASA 5500 Series Adaptive Security Appliance 7.0 before 7.0(8.10), 7.2 before 7.2(4.45), 8.0 before 8.0(4.44), 8.1 before 8.1(2.35), and 8.2 before 8.2(1.10) allows remote attackers to cause a denial of service (device reload) via a malformed TCP segment when certain NAT translation and Cisco AIP-SSM configurations are used, aka Bug ID CSCtb37219.

Cisco VPN 3000 series concentrators before 2.5.2(F) allow remote attackers to cause a denial of service via a flood of invalid login requests to (1) the SSL service, or (2) the telnet service, which do not properly disconnect the user after several failed login attempts.

The IOS HTTP service in Cisco routers and switches running IOS 11.1 through 12.1 allows remote attackers to cause a denial of service by requesting a URL that contains a %% string.

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.

A vulnerability in the Border Gateway Protocol (BGP) over an Ethernet Virtual Private Network (EVPN) for Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload, resulting in a denial of service (DoS) condition, or potentially corrupt the BGP routing table, which could result in network instability. The vulnerability exists due to changes in the implementation of the BGP MPLS-Based Ethernet VPN RFC (RFC 7432) draft between IOS XE software releases. When the BGP Inclusive Multicast Ethernet Tag Route or BGP EVPN MAC/IP Advertisement Route update packet is received, it could be possible that the IP address length field is miscalculated. An attacker could exploit this vulnerability by sending a crafted BGP packet to an affected device after the BGP session was established. An exploit could allow the attacker to cause the affected device to reload or corrupt the BGP routing table; either outcome would result in a DoS. The vulnerability may be triggered when the router receives a crafted BGP message from a peer on an existing BGP session. This vulnerability affects all releases of Cisco IOS XE Software prior to software release 16.3 that support BGP EVPN configurations. If the device is not configured for EVPN, it is not vulnerable. Cisco Bug IDs: CSCui67191, CSCvg52875.

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS 15.0 through 15.6 and Cisco IOS XE 3.5 through 16.5 could allow an unauthenticated, remote attacker to cause high CPU utilization, traceback messages, or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to how an affected device processes certain IKEv2 packets. An attacker could exploit this vulnerability by sending specific IKEv2 packets to an affected device to be processed. A successful exploit could allow the attacker to cause high CPU utilization, traceback messages, or a reload of the affected device that leads to a DoS condition. This vulnerability affects Cisco devices that have the Internet Security Association and Key Management Protocol (ISAKMP) enabled. Although only IKEv2 packets can be used to trigger this vulnerability, devices that are running Cisco IOS Software or Cisco IOS XE Software are vulnerable when ISAKMP is enabled. A device does not need to be configured with any IKEv2-specific features to be vulnerable. Many features use IKEv2, including different types of VPNs such as the following: LAN-to-LAN VPN; Remote-access VPN, excluding SSL VPN; Dynamic Multipoint VPN (DMVPN); and FlexVPN. Cisco Bug IDs: CSCvc41277.

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 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 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 HTTP Server feature of Cisco IOS XE Software when the Telephony Service feature is enabled could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to a null pointer dereference when accessing specific URLs. An attacker could exploit this vulnerability by sending crafted HTTP traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, causing a DoS condition on the affected device.

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

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

A vulnerability in the 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.

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 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.

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.

A vulnerability in the SSL VPN feature for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to a logic error in memory management when the device is handling SSL VPN connections. An attacker could exploit this vulnerability by sending crafted SSL/TLS packets to the SSL VPN server of the affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

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

A vulnerability in the 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.

Cisco IOS 12.0 through 12.4, when IP-based tunnels and the Cisco Express Forwarding feature are enabled, allows remote attackers to cause a denial of service (device reload) via malformed packets, aka Bug ID CSCsx70889.

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

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

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

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.