A vulnerability in the DHCP version 4 (DHCPv4) server feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to trigger a crash of the dhcpd process, resulting in a denial of service (DoS) condition. This vulnerability exists because certain DHCPv4 messages are improperly validated when they are processed by an affected device. An attacker could exploit this vulnerability by sending a malformed DHCPv4 message to an affected device. A successful exploit could allow the attacker to cause a crash of the dhcpd process. While the dhcpd process is restarting, which may take approximately two minutes, DHCPv4 server services are unavailable on the affected device. This could temporarily prevent network access to clients that join the network during that time period and rely on the DHCPv4 server of the affected device. Notes: Only the dhcpd process crashes and eventually restarts automatically. The router does not reload. This vulnerability only applies to DHCPv4. DHCP version 6 (DHCPv6) is not affected.

A vulnerability in the Secure Copy Protocol (SCP) and SFTP feature of Cisco IOS XR Software could allow an authenticated, local attacker to create or overwrite files in a system directory, which could lead to a denial of service (DoS) condition. The attacker would require valid user credentials to perform this attack. This vulnerability is due to a lack of proper validation of SCP and SFTP CLI input parameters. An attacker could exploit this vulnerability by authenticating to the device and issuing SCP or SFTP CLI commands with specific parameters. A successful exploit could allow the attacker to impact the functionality of the device, which could lead to a DoS condition. The device may need to be manually rebooted to recover. Note: This vulnerability is exploitable only when a local user invokes SCP or SFTP commands at the Cisco IOS XR CLI. A local user with administrative privileges could exploit this vulnerability remotely.

A vulnerability in the Web Authentication feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct a reflected cross-site scripting attack (XSS) on an affected device. This vulnerability is due to improper sanitization of user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a malicious link. A successful exploit could allow the attacker to execute a reflected XSS attack and steal user cookies from the affected device.

A vulnerability in the access control list (ACL) processing on MPLS interfaces in the ingress direction of Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to improper assignment of lookup keys to internal interface contexts. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to access resources behind the affected device that were supposed to be protected by a configured ACL.

A vulnerability in the implementation of the CLI on a device that is running ConfD could allow an authenticated, local attacker to perform a command injection attack. The vulnerability is due to insufficient validation of a process argument on an affected device. An attacker could exploit this vulnerability by injecting commands during the execution of this process. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with the privilege level of ConfD, which is commonly root.

Cisco IOS, IOS XE, Secure Firewall Adaptive Security Appliance, and Secure Firewall Threat Defense Software IKEv2 Denial of Service Vulnerability

A vulnerability in the IKEv2 feature of Cisco IOS Software, IOS XE Software, Secure Firewall ASA Software, and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to reload, resulting in a DoS condition. This vulnerability is due to the improper processing of IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. A successful exploit could allow the attacker to cause an infinite loop that exhausts resources and could cause the device to reload.

A vulnerability in Cisco IOS XE Software could allow an authenticated, local attacker with level-15 privileges or an unauthenticated attacker with physical access to an affected device to execute persistent code at boot time and break the chain of trust. This vulnerability is due to improper validation of software packages. An attacker could exploit this vulnerability by placing a crafted file into a specific location on an affected device. A successful exploit could allow the attacker to execute persistent code on the underlying operating system. Because this vulnerability allows an attacker to bypass a major security feature of a device, Cisco has raised the Security Impact Rating (SIR) of this advisory from Medium to High.

Cisco IOS XR Software Management Interface ACL Bypass Vulnerability

A vulnerability in the management interface access control list (ACL) processing feature in Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass configured ACLs for the SSH, NetConf, and gRPC features. This vulnerability exists because management interface ACLs have not been supported on Cisco IOS XR Software Packet I/O infrastructure platforms for Linux-handled features such as SSH, NetConf, or gRPC. An attacker could exploit this vulnerability by attempting to send traffic to an affected device. A successful exploit could allow the attacker to bypass an ingress ACL that is applied on the management interface of the affected device.

A vulnerability in the HTTP API subsystem of Cisco IOS XE Software could allow a remote attacker to inject commands that will execute with root privileges into the underlying operating system. This vulnerability is due to insufficient input validation. An attacker with administrative privileges could exploit this vulnerability by authenticating to an affected system and performing an API call with crafted input. Alternatively, an unauthenticated attacker could persuade a legitimate user with administrative privileges who is currently logged in to the system to click a crafted link. A successful exploit could allow the attacker to execute arbitrary commands as the root user.

Cisco IOS XR Address Resolution Protocol Broadcast Storm Vulnerability

A vulnerability in the Address Resolution Protocol (ARP) implementation of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to trigger a broadcast storm, leading to a denial of service (DoS) condition on an affected device.  This vulnerability is due to how Cisco IOS XR Software processes a high, sustained rate of ARP traffic hitting the management interface. Under certain conditions, an attacker could exploit this vulnerability by sending an excessive amount of traffic to the management interface of an affected device, overwhelming its ARP processing capabilities. A successful exploit could result in degraded device performance, loss of management connectivity, and complete unresponsiveness of the system, leading to a DoS condition.

Stored Cross‑Site Scripting in Cisco IOS XE Web Interface

A vulnerability in the web-based Cisco IOx application hosting environment management interface of Cisco IOS XE Software could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the web-based management interface of an affected device. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by injecting malicious code into specific pages of the interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information. To exploit this vulnerability, the attacker must have valid administrative credentials.

Unauthenticated CRLF Injection in Cisco IOx Log Management

A vulnerability in the web-based Cisco IOx application hosting environment management interface of Cisco IOS XE Software could allow an unauthenticated, remote attacker to perform a carriage return line feed (CRLF) injection attack against a user. This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by sending crafted packets to an affected device. A successful exploit could allow the attacker to arbitrarily inject log entries, manipulate the structure of log files, or obscure legitimate log events.

Authenticated DoS via Malformed SCP Request on Cisco IOS XE

A vulnerability in the Secure Copy Protocol (SCP) server feature of Cisco IOS XE Software could allow an authenticated, local attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of a malformed SCP request. An attacker could exploit this vulnerability by issuing a crafted command through SSH. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.

Authenticated Local Attacker Can Force Cisco IOS XE Into Maintenance Mode, Causing Denial of Service

A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability exists because incorrect privileges are associated with the start maintenance command. An attacker could exploit this vulnerability by accessing the management CLI of the affected device as a low-privileged user and using the start maintenance command. A successful exploit could allow the attacker to put the device in maintenance mode, which shuts down interfaces, resulting in a denial of service (DoS) condition. In case of exploitation, a device administrator can connect to the CLI and use the stop maintenance command to restore operations.

Remote Denial of Service via Malformed CAPWAP Packet on Cisco IOS XE Wireless Controller

A vulnerability in the processing of Control and Provisioning of Wireless Access Points (CAPWAP) packets of Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family 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 a malformed CAPWAP packet. An attacker could exploit this vulnerability by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload unexpectedly, resulting in a DoS condition.

Authenticated HTTP Server Exploit Causing Device Reload and Denial of Service

A vulnerability in the HTTP Server feature of Cisco IOS Software and Cisco IOS XE Software Release 3E could allow an authenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending malformed HTTP requests to an affected device. A successful exploit could allow the attacker to cause a watchdog timer to expire and the device to reload, resulting in a DoS condition. To exploit this vulnerability, the attacker must have a valid user account.

Elevated Privilege via Unvalidated Lobby Ambassador API Parameters

A vulnerability in the Lobby Ambassador web-based management API of Cisco IOS XE Software could allow an authenticated, remote attacker to elevate their privileges and access management APIs that would not normally be available for Lobby Ambassador users. This vulnerability exists because parameters that are received by an API endpoint are not sufficiently validated. An attacker could exploit this vulnerability by authenticating as a Lobby Ambassador user and sending a crafted HTTP request to an affected device. A successful exploit could allow the attacker to create a new user with privilege level 1 access to the web-based management API. The attacker would then be able to access the device with these new credentials and privileges.

Unencrypted Configuration Upload Allows Device Information Disclosure in Cisco Meraki

A vulnerability in Cisco IOS XE Software for Cisco Meraki could allow a remote, unauthenticated attacker to view confidential device information. This vulnerability is due to a device configuration upload being performed over an insecure tunnel. An attacker could exploit this vulnerability by conducting an on-path attack between the affected device and the Cisco Meraki Dashboard. A successful exploit could allow the attacker to view sensitive device configuration information.

Cisco IOS XR Software CLI Privilege Escalation Vulnerability

A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of user arguments that are passed to specific CLI commands. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root and execute arbitrary commands on the underlying operating system.

Cisco IOS XR Software Multi-Instance Intermediate System-to-Intermediate System Denial of Service Vulnerability

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly. This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and must have formed an adjacency.