Multiple vulnerabilities in image verification checks of Cisco Network Convergence System (NCS) 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for Cisco 8000 Series Routers could allow an authenticated, local attacker to execute arbitrary code on the underlying operating system. For more information about these vulnerabilities, see the Details section of this advisory.

Multiple vulnerabilities in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to gain access to the underlying root shell of an affected device and execute arbitrary commands with root privileges. For more information about these vulnerabilities, see the Details section of this advisory.

The SCP and SFTP modules in Cisco IOS XR 5.0.0 through 5.2.5 on Network Convergence System 6000 devices use weak permissions for system files, which allows remote authenticated users to cause a denial of service (overwrite) via unspecified vectors, aka Bug ID CSCuw75848.

A vulnerability in the implementation of Border Gateway Protocol (BGP) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected system. The vulnerability is due to incorrect processing of certain BGP update messages. An attacker could exploit this vulnerability by sending BGP update messages that include a specific set of attributes to be processed by an affected system. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP traffic from explicitly defined peers only. To exploit this vulnerability, the malicious BGP update message would need to come from a configured, valid BGP peer or would need to be injected by the attacker into the victim's BGP network on an existing, valid TCP connection to a BGP peer.

A vulnerability in the implementation of Border Gateway Protocol (BGP) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain BGP update messages. An attacker could exploit this vulnerability by sending BGP update messages that include a specific, malformed attribute to be processed by an affected system. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP traffic only from explicitly defined peers. To exploit this vulnerability, the malicious BGP update message would need to come from a configured, valid BGP peer, or would need to be injected by the attacker into the victim's BGP network on an existing, valid TCP connection to a BGP peer.

A vulnerability in the implementation of the Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the incorrect processing of a BGP update message that contains specific EVPN attributes. An attacker could exploit this vulnerability by sending a BGP update message that contains specific EVPN attributes. To exploit this vulnerability, an attacker must control a BGP speaker that has an established trusted peer connection to an affected device that is configured with the address family L2VPN EVPN to receive and process the update message. This vulnerability cannot be exploited by any data that is initiated by clients on the Layer 2 network or by peers that are not configured to accept the L2VPN EVPN address family. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP updates only from explicitly defined peers. For this vulnerability to be exploited, the malicious BGP update message must either come from a configured, valid BGP peer or be injected by the attacker into the affected BGP network on an existing, valid TCP connection to a BGP peer. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgpevpn-zWTRtPBb This advisory is part of the April 2022 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: April 2022 Cisco IOS XR Software Security Advisory Bundled Publication.

A vulnerability in the boot process of Cisco IOS XR Software could allow an authenticated, local attacker with high privileges to bypass the Cisco Secure Boot functionality and load unverified software on an affected device. To exploit this successfully, the attacker must have root-system privileges on the affected device. This vulnerability is due to an error in the software build process. An attacker could exploit this vulnerability by manipulating the system’s configuration options to bypass some of the integrity checks that are performed during the booting process. A successful exploit could allow the attacker to control the boot configuration, which could enable them to bypass of the requirement to run Cisco signed images or alter the security properties of the running system.

Multiple vulnerabilities in Cisco Network Convergence System (NCS) 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for the Cisco 8000 Series Routers could allow an authenticated, local attacker to execute unsigned code during the boot process on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Multiple vulnerabilities in Cisco Network Convergence System (NCS) 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for the Cisco 8000 Series Routers could allow an authenticated, local attacker to execute unsigned code during the boot process on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Multiple vulnerabilities in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to gain access to the underlying root shell of an affected device and execute arbitrary commands with root privileges. For more information about these vulnerabilities, see the Details section of this advisory. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-cmd-inj-wbZKvPxc This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication.

A vulnerability in the CLI of Cisco IOS XR 64-Bit Software could allow an authenticated, local attacker to inject arbitrary commands that are executed with root privileges on the underlying Linux operating system (OS) of an affected device. This vulnerability is due to insufficient input validation of commands that are supplied by the user. An attacker could exploit this vulnerability by authenticating to a device and submitting crafted input to an affected command. A successful exploit could allow the attacker to execute commands on the underlying Linux OS with root privileges. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xr-cmdinj-vsKGherc

A vulnerability in the Connectivity Fault Management (CFM) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to incorrect processing of invalid continuity check messages (CCMs). An attacker could exploit this vulnerability by sending crafted CCMs to an affected device. A successful exploit could allow the attacker to cause the CFM service to crash when a user displays information about maintenance end points (MEPs) for peer MEPs on an affected device.

A vulnerability in the IPv6 traffic processing of Cisco IOS XR Software and Cisco NX-OS Software for certain Cisco devices could allow an unauthenticated, remote attacker to bypass an IPv6 access control list (ACL) that is configured for an interface of an affected device. The vulnerability is due to improper processing of IPv6 traffic that is sent through an affected device. An attacker could exploit this vulnerability by sending crafted IPv6 packets that traverse the affected device. A successful exploit could allow the attacker to access resources that would typically be protected by the interface ACL.

A vulnerability in the health check RPM of Cisco IOS XR Software could allow an unauthenticated, remote attacker to access the Redis instance that is running within the NOSi container. This vulnerability exists because the health check RPM opens TCP port 6379 by default upon activation. An attacker could exploit this vulnerability by connecting to the Redis instance on the open port. A successful exploit could allow the attacker to write to the Redis in-memory database, write arbitrary files to the container filesystem, and retrieve information about the Redis database. Given the configuration of the sandboxed container that the Redis instance runs in, a remote attacker would be unable to execute remote code or abuse the integrity of the Cisco IOS XR Software host system. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-redis-ABJyE5xK

Cisco IOS XR on Trident line cards in ASR 9000 devices lacks a static punt policer, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted packets, aka Bug ID CSCun83985.

Cisco IOS XR 4.3(.2) and earlier on ASR 9000 devices does not properly perform NetFlow sampling of IP packets, which allows remote attackers to cause a denial of service (chip and card hangs) via malformed (1) IPv4 or (2) IPv6 packets, aka Bug ID CSCuo68417.

Cisco IOS XR 5.1 and earlier on Network Convergence System 6000 devices allows remote attackers to cause a denial of service (NPU and card hang or reload) via a malformed MPLS packet, aka Bug ID CSCuq10466.

A vulnerability in the access control list (ACL) processing on Pseudowire 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 access control list (ACL) processing in the egress direction of Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability exists because certain packets are handled incorrectly when they are received on an ingress interface on one line card and destined out of an egress interface on another line card where the egress ACL is configured. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an egress ACL on the affected device. For more information about this vulnerability, see the section of this advisory. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

A vulnerability in the hybrid access control list (ACL) processing of IPv4 packets in Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect handling of packets when a specific configuration of the hybrid ACL exists. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass a configured ACL on the affected device. For more information, see the section of this advisory. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.

A vulnerability in the classic access control list (ACL) compression feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass the protection that is offered by a configured ACL on an affected device. This vulnerability is due to incorrect destination address range encoding in the compression module of an ACL that is applied to an interface of an affected device. An attacker could exploit this vulnerability by sending traffic through the affected device that should be denied by the configured ACL. A successful exploit could allow the attacker to bypass configured ACL protections on the affected device, allowing the attacker to access trusted networks that the device might be protecting. There are workarounds that address this vulnerability. This advisory is part of the September 2023 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2023 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication .

A vulnerability in the Protocol Independent Multicast (PIM) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the PIM process to restart, resulting in a denial of service condition on an affected device. The vulnerability is due to the incorrect processing of crafted AutoRP packets. An attacker could exploit this vulnerability by sending crafted packets to port UDP 496 on a reachable IP address on the device. A successful exploit could allow the attacker to cause the PIM process to restart. There are workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-iosxr-pim-dos

A vulnerability in the IPv6 traffic processing of Cisco IOS XR Software and Cisco NX-OS Software for certain Cisco devices could allow an unauthenticated, remote attacker to bypass an IPv6 access control list (ACL) that is configured for an interface of an affected device. The vulnerability is due to improper processing of IPv6 traffic that is sent through an affected device. An attacker could exploit this vulnerability by sending crafted IPv6 packets that traverse the affected device. A successful exploit could allow the attacker to access resources that would typically be protected by the interface ACL. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipv6-acl-CHgdYk8j

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 NULL pointer dereference, resulting in a crash of the dhcpd process. While the dhcpd process is restarting, which may take up to 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. Note: Only the dhcpd process crashes and eventually restarts automatically. The router does not reload. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dhcp-dos-pjPVReLU This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication.

Cisco IOS XR 4.3.4 and earlier on ASR 9000 devices, when bridge-group virtual interface (BVI) routing is enabled, allows remote attackers to cause a denial of service (chip and card hangs) via a series of crafted MPLS packets, aka Bug ID CSCuo91149.

Cisco IOS XR 5.3.1 on ASR 9000 devices allows remote attackers to cause a denial of service (NPU chip reset or line-card reload) by sending crafted IEEE 802.3x flow-control PAUSE frames on the local network, aka Bug ID CSCut19959.

A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to read any file in the file system of the underlying Linux operating system. The attacker must have valid credentials on the affected device. This vulnerability is due to incorrect validation of the arguments that are passed to a specific CLI command. An attacker could exploit this vulnerability by logging in to an affected device with low-privileged credentials and using the affected command. A successful exploit could allow the attacker access files in read-only mode on the Linux file system.

A vulnerability in the Cisco IOS XR Software CLI could allow an authenticated, local attacker to view more information than their privileges allow. This vulnerability is due to insufficient application of restrictions during the execution of a specific command. An attacker could exploit this vulnerability by running a specific command. A successful exploit could allow the attacker to view sensitive configuration information that their privileges might not otherwise allow them to access.

A vulnerability in the CLI parser of Cisco IOS XR Software could allow an authenticated, local attacker to view more information than their privileges allow. The vulnerability is due to insufficient application of restrictions during the execution of a specific command. An attacker could exploit this vulnerability by using a specific command at the command line. A successful exploit could allow the attacker to obtain sensitive information within the configuration that otherwise might not have been accessible beyond the privileges of the invoking user.