A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated user in possession of Administrator credentials to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of arguments that are passed to specific configuration CLI commands. An attacker could exploit this vulnerability by including crafted input as the argument of an affected configuration CLI command. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with the privileges of root. Note: To successfully exploit this vulnerability on a Cisco NX-OS device, an attacker must have Administrator credentials. The following Cisco devices already allow administrative users to access the underlying operating system through the bash-shell feature, so, for these devices, this vulnerability does not grant any additional privileges: Nexus 3000 Series Switches Nexus 7000 Series Switches that are running Cisco NX-OS Software releases 8.1(1) and later Nexus 9000 Series Switches in standalone NX-OS mode

A vulnerability in the Link Layer Discovery Protocol (LLDP) feature of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of specific fields in an LLDP frame. An attacker could exploit this vulnerability by sending a crafted LLDP packet to an interface of an affected device and having an authenticated user retrieve LLDP statistics from the affected device through CLI show commands or Simple Network Management Protocol (SNMP) requests. A successful exploit could allow the attacker to cause the LLDP service to crash and stop running on the affected device. In certain situations, the LLDP crash may result in a reload of the affected device. Note: LLDP is a Layer 2 link protocol. To exploit this vulnerability, an attacker would need to be directly connected to an interface of an affected device, either physically or logically (for example, through a Layer 2 Tunnel configured to transport the LLDP protocol).

A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of arguments that are passed to specific CLI commands. An attacker could exploit this vulnerability by including crafted input as the argument of an affected command. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with the privileges of the currently logged-in user.

A vulnerability in the Cisco Discovery Protocol feature of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code with root privileges or cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper input validation of specific values that are within a Cisco Discovery Protocol message. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to execute arbitrary code with root privileges or cause the Cisco Discovery Protocol process to crash and restart multiple times, which would cause the affected device to reload, resulting in a DoS condition. Note: Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

A vulnerability in the OSPF version 3 (OSPFv3) 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 incomplete input validation of specific OSPFv3 packets. An attacker could exploit this vulnerability by sending a malicious OSPFv3 link-state advertisement (LSA) to an affected device. A successful exploit could allow the attacker to cause the OSPFv3 process to crash and restart multiple times, causing the affected device to reload and resulting in a DoS condition. Note: The OSPFv3 feature is disabled by default. To exploit this vulnerability, an attacker must be able to establish a full OSPFv3 neighbor state with an affected device. For more information about exploitation conditions, see the Details section of this advisory.

A vulnerability in the Cisco Discovery Protocol service of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause the service to restart, resulting in a denial of service (DoS) condition. This vulnerability is due to improper handling of Cisco Discovery Protocol messages that are processed by the Cisco Discovery Protocol service. An attacker could exploit this vulnerability by sending a series of malicious Cisco Discovery Protocol messages to an affected device. A successful exploit could allow the attacker to cause the Cisco Discovery Protocol service to fail and restart. In rare conditions, repeated failures of the process could occur, which could cause the entire device to restart.

A vulnerability in the Unidirectional Link Detection (UDLD) feature of Cisco FXOS Software, Cisco IOS Software, Cisco IOS XE Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload. This vulnerability is due to improper input validation of the UDLD packets. An attacker could exploit this vulnerability by sending specifically crafted UDLD packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: The UDLD feature is disabled by default, and the conditions to exploit this vulnerability are strict. An attacker must have full control of a directly connected device. On Cisco IOS XR devices, the impact is limited to the reload of the UDLD process.

A vulnerability in the implementation of the system login block-for command for Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a login process to unexpectedly restart, causing a denial of service (DoS) condition. This vulnerability is due to a logic error in the implementation of the system login block-for command when an attack is detected and acted upon. An attacker could exploit this vulnerability by performing a brute-force login attack on an affected device. A successful exploit could allow the attacker to cause a login process to reload, which could result in a delay during authentication to the affected device.

A vulnerability in the network stack 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 the software improperly releases resources when it processes certain IPv6 packets that are destined to an affected device. An attacker could exploit this vulnerability by sending multiple crafted IPv6 packets to an affected device. A successful exploit could cause the network stack to run out of available buffers, impairing operations of control plane and management plane protocols and resulting in a DoS condition. Manual intervention would be required to restore normal operations on the affected device. For more information about the impact of this vulnerability, see the Details section of this advisory.

A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause an NX-API system process to unexpectedly restart. The vulnerability is due to incorrect validation of the HTTP header of a request that is sent to the NX-API. An attacker could exploit this vulnerability by sending a crafted HTTP request to the NX-API on an affected device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition in the NX-API service; however, the Cisco NX-OS device itself would still be available and passing network traffic. Note: The NX-API feature is disabled by default.

A vulnerability in the Cisco Discovery Protocol feature of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code as root or cause a denial of service (DoS) condition on an affected device. The vulnerability exists because of insufficiently validated Cisco Discovery Protocol packet headers. An attacker could exploit this vulnerability by sending a crafted Cisco Discovery Protocol packet to a Layer 2-adjacent affected device. A successful exploit could allow the attacker to cause a buffer overflow that could allow the attacker to execute arbitrary code as root or cause a DoS condition on the affected device. Note: Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent). Note: This vulnerability is different from the following Cisco FXOS and NX-OS Software Cisco Discovery Protocol vulnerabilities that Cisco announced on Feb. 5, 2020: Cisco FXOS, IOS XR, and NX-OS Software Cisco Discovery Protocol Denial of Service Vulnerability and Cisco NX-OS Software Cisco Discovery Protocol Remote Code Execution Vulnerability.

A vulnerability in the anycast gateway feature of Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a device to learn invalid Address Resolution Protocol (ARP) entries. The ARP entries are for nonlocal IP addresses for the subnet. The vulnerability is due to improper validation of a received gratuitous ARP (GARP) request. An attacker could exploit this vulnerability by sending a malicious GARP packet on the local subnet to cause the ARP table on the device to become corrupted. A successful exploit could allow the attacker to populate the ARP table with incorrect entries, which could lead to traffic disruptions.

A vulnerability in the Cisco Discovery Protocol implementation for Cisco FXOS Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a missing check when the affected software processes Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to exhaust system memory, causing the device to reload. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

A vulnerability in a CLI command related to the virtualization manager (VMAN) in Cisco NX-OS Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying Linux operating system with root privileges. The vulnerability is due to insufficient validation of arguments passed to a specific VMAN CLI command on an affected device. An attacker could exploit this vulnerability by including malicious input as the argument of an affected command. A successful exploit could allow the attacker to execute arbitrary commands on the underlying Linux operating system with root privileges, which may lead to complete system compromise. An attacker would need valid administrator credentials to exploit this vulnerability.

A vulnerability in Cisco NX-OS Software and Cisco IOS XE Software could allow an authenticated, local attacker with valid administrator or privilege level 15 credentials to load a virtual service image and bypass signature verification on an affected device. The vulnerability is due to improper signature verification during the installation of an Open Virtual Appliance (OVA) image. An authenticated, local attacker could exploit this vulnerability and load a malicious, unsigned OVA image on an affected device. A successful exploit could allow an attacker to perform code execution on a crafted software OVA image.

A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause an NX-API system process to unexpectedly restart. The vulnerability is due to incorrect validation of the HTTP header of a request that is sent to the NX-API. An attacker could exploit this vulnerability by sending a crafted HTTP request to the NX-API on an affected device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition in the NX-API service; however, the NX-OS device itself would still be available and passing network traffic. Note: The NX-API feature is disabled by default.

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 MODEPRIVATE (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 Link Layer Discovery Protocol (LLDP) implementation for Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition when the device unexpectedly reloads. The vulnerability is due to improper input validation of certain type, length, value (TLV) fields of the LLDP frame header. An attacker could exploit this vulnerability by sending a crafted LLDP packet to an interface on the targeted device. A successful exploit could allow the attacker to cause the switch to reload unexpectedly.

A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to craft a packet to the management interface on an affected system, causing a buffer overflow. The vulnerability is due to incorrect input validation in the authentication module of the NX-API subsystem. An attacker could exploit this vulnerability by sending a crafted HTTP or HTTPS packet to the management interface of an affected system with the NX-API feature enabled. An exploit could allow the attacker to execute arbitrary code as root. Note: NX-API is disabled by default. This vulnerability affects: MDS 9000 Series Multilayer Switches, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules. Cisco Bug IDs: CSCvd45804, CSCve02322, CSCve02412.

A vulnerability in the authentication, authorization, and accounting (AAA) implementation of Cisco Firepower Extensible Operating System (FXOS) and NX-OS System Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability occurs because AAA processes prevent the NX-OS System Manager from receiving keepalive messages when an affected device receives a high rate of login attempts, such as in a brute-force login attack. System memory can run low on the FXOS devices under the same conditions, which could cause the AAA process to unexpectedly restart or cause the device to reload. An attacker could exploit this vulnerability by performing a brute-force login attack against a device that is configured with AAA security services. A successful exploit could allow the attacker to cause the affected device to reload. This vulnerability affects the following Cisco products if they are running Cisco FXOS or NX-OS System Software that is configured for AAA services: Firepower 4100 Series Next-Generation Firewall, Firepower 9300 Security Appliance, Multilayer Director Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Switches, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, Unified Computing System (UCS) 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCuq58760, CSCuq71257, CSCur97432, CSCus05214, CSCux54898, CSCvc33141, CSCvd36971, CSCve03660.

Cisco NX-OS 4.0 through 7.3 and 11.0 through 11.2 on 1000v, 2000, 3000, 3500, 5000, 5500, 5600, 6000, 7000, 7700, and 9000 devices allows remote attackers to cause a denial of service (device reload) by leveraging a peer relationship to send a crafted BGP UPDATE message, aka Bug IDs CSCuq77105 and CSCux11417.

Cisco NX-OS 4.1 through 7.3 and 11.0 through 11.2 on Nexus 2000, 3000, 3500, 5000, 5500, 5600, 6000, 7000, 7700, and 9000 devices allows remote attackers to cause a denial of service (device crash) via malformed IPv4 DHCP packets to the DHCPv4 relay agent, aka Bug IDs CSCuq39250, CSCus21733, CSCus21739, CSCut76171, and CSCux67182.

Cisco NX-OS 4.1 through 7.3 and 11.0 through 11.2 on Nexus 2000, 5000, 5500, 5600, 6000, 7000, 7700, and 9000 devices allows remote attackers to cause a denial of service (device crash) via crafted IPv4 DHCP packets to the (1) DHCPv4 relay agent or (2) smart relay agent, aka Bug IDs CSCuq24603, CSCur93159, CSCus21693, and CSCut76171.

The DHCP implementation in the PowerOn Auto Provisioning (POAP) feature in Cisco NX-OS does not properly restrict the initialization process, which allows remote attackers to execute arbitrary commands as root by sending crafted response packets on the local network, aka Bug ID CSCur14589.