A vulnerability in the IPv6 DHCP (DHCPv6) client module of Cisco Adaptive Security Appliance (ASA) Software, Cisco Firepower Threat Defense (FTD) Software, Cisco IOS Software, and 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 DHCPv6 messages. An attacker could exploit this vulnerability by sending crafted DHCPv6 messages to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: To successfully exploit this vulnerability, the attacker would need to either control the DHCPv6 server or be in a man-in-the-middle position.
A vulnerability in Cisco IOS XE Software for Cisco Catalyst 9300 Series Switches could allow an authenticated, local attacker with level-15 privileges or an unauthenticated attacker with physical access to the device to execute persistent code at boot time and break the chain of trust. This vulnerability is due to errors that occur when retrieving the public release key that is used for image signature verification. An attacker could exploit this vulnerability by modifying specific variables in the Serial Peripheral Interface (SPI) flash memory of an affected device. A successful exploit could allow the attacker to execute persistent code on the underlying operating system. Note: In Cisco IOS XE Software releases 16.11.1 and later, the complexity of an attack using this vulnerability is high. However, an attacker with level-15 privileges could easily downgrade the Cisco IOS XE Software on a device to a release that would lower the attack complexity.
A vulnerability in the implementation of the IPv4 Virtual Fragmentation Reassembly (VFR) 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 improper reassembly of large packets that occurs when VFR is enabled on either a tunnel interface or on a physical interface that is configured with a maximum transmission unit (MTU) greater than 4,615 bytes. An attacker could exploit this vulnerability by sending fragmented packets through a 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.
A vulnerability in the Meraki onboarding feature of Cisco IOS XE Software could allow an authenticated, local attacker to gain root level privileges on an affected device. This vulnerability is due to insufficient memory protection in the Meraki onboarding feature of an affected device. An attacker could exploit this vulnerability by modifying the Meraki registration parameters. A successful exploit could allow the attacker to elevate privileges to root.
A vulnerability in the Cisco IOx application hosting environment could allow an authenticated, remote attacker to execute arbitrary commands as root on the underlying host operating system. This vulnerability is due to incomplete sanitization of parameters that are passed in for activation of an application. An attacker could exploit this vulnerability by deploying and activating an application in the Cisco IOx application hosting environment with a crafted activation payload file. A successful exploit could allow the attacker to execute arbitrary commands as root on the underlying host operating system.
A vulnerability in the DNS application layer gateway (ALG) functionality that is used by Network Address Translation (NAT) in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. This vulnerability is due to a logic error that occurs when an affected device inspects certain TCP DNS packets. An attacker could exploit this vulnerability by sending crafted DNS packets through the affected device that is performing NAT for DNS packets. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition on the affected device. Note: This vulnerability can be exploited only by sending IPv4 TCP packets through an affected device. This vulnerability cannot be exploited by sending IPv6 traffic.
A vulnerability in the egress MPLS packet processing function of Cisco IOS XE Software for Cisco Catalyst 3650, Catalyst 3850, and Catalyst 9000 Family Switches 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 insufficient input validation of IPv4 traffic. An attacker could exploit this vulnerability by sending a malformed packet out of an affected MPLS-enabled interface. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
A vulnerability in the implementation of IPv6 VPN over MPLS (6VPE) with Zone-Based Firewall (ZBFW) of Cisco IOS XE 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 error handling of an IPv6 packet that is forwarded from an MPLS and ZBFW-enabled interface in a 6VPE deployment. An attacker could exploit this vulnerability by sending a crafted IPv6 packet sourced from a device on the IPv6-enabled virtual routing and forwarding (VRF) interface through the affected device. A successful exploit could allow the attacker to reload the device, resulting in a DoS condition.
A vulnerability in the SSH implementation of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload. This vulnerability is due to improper handling of resources during an exceptional situation. An attacker could exploit this vulnerability by continuously connecting to an affected device and sending specific SSH requests. A successful exploit could allow the attacker to cause the affected device to reload.
A vulnerability in the software image verification functionality of Cisco IOS XE Software for Cisco Catalyst 9200 Series Switches could allow an unauthenticated, physical attacker to execute unsigned code at system boot time. This vulnerability is due to an improper check in the code function that manages the verification of the digital signatures of system image files during the initial boot process. An attacker could exploit this vulnerability by loading unsigned software on an affected device. A successful exploit could allow the attacker to boot a malicious software image or execute unsigned code and bypass the image verification check part of the boot process of the affected device. To exploit this vulnerability, the attacker needs either unauthenticated physical access to the device or privileged access to the root shell on the device. Note: In Cisco IOS XE Software releases 16.11.1 and later, root shell access is protected by the Consent Token mechanism. However, an attacker with level-15 privileges could easily downgrade the Cisco IOS XE Software running on a device to a release where root shell access is more readily available.