A vulnerability in the Switch Integrated Security Features of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an interface queue wedge. The vulnerability is due to incorrect handling of crafted IPv6 packets. An attacker could exploit this vulnerability by sending crafted IPv6 packets through the device. An exploit could allow the attacker to cause an interface queue wedge. This vulnerability affects the Cisco cBR-8 Converged Broadband Router, Cisco ASR 1000 Series Aggregation Services Routers, and Cisco Cloud Services Router 1000V Series when configured with IPv6. In the field and internal testing, this vulnerability was only observed or reproduced on the Cisco cBR-8 Converged Broadband Router. The Cisco ASR 1000 Series Aggregation Services Routers and Cisco Cloud Services Router 1000V Series contain the same code logic, so affected trains have had the code fix applied; however, on these two products, the vulnerability has not been observed in the field or successfully reproduced internally. Cisco Bug IDs: CSCvd75185.

A vulnerability in Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper management of memory resources, referred to as a double free. An attacker could exploit this vulnerability by sending crafted SNMP packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. To exploit this vulnerability via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for an affected system. To exploit this vulnerability via SNMP Version 3, the attacker must know the user credentials for the affected system. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software, have been configured to be queried over SNMP, and have Network Address Translation (NAT) enabled. Cisco Bug IDs: CSCve75818.

A vulnerability in the implementation of Internet Key Exchange Version 1 (IKEv1) functionality in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of specific IKEv1 packets. An attacker could exploit this vulnerability by sending crafted IKEv1 packets to an affected device during an IKE negotiation. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuj73916.

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device to be processed. A successful exploit could cause an affected device to continuously consume memory and eventually reload, resulting in a DoS condition. Cisco Bug IDs: CSCvf22394.

A vulnerability in the Zone-Based Firewall code of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a device to reload. The vulnerability is due to the way fragmented packets are handled in the firewall code. An attacker could exploit this vulnerability by sending fragmented IP Version 4 or IP Version 6 packets through an affected device. An exploit could allow the attacker to cause the device to crash, resulting in a denial of service (DoS) condition. The following releases of Cisco IOS XE Software are vulnerable: Everest-16.4.1, Everest-16.4.2, Everest-16.5.1, Everest-16.5.1b, Everest-16.6.1, Everest-16.6.1a. Cisco Bug IDs: CSCvf60296.

A vulnerability in the Smart Install feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of packet data. An attacker could exploit this vulnerability by sending a crafted packet to an affected device on TCP port 4786. Only Smart Install client switches are affected. Cisco devices that are configured as a Smart Install director are not affected by this vulnerability. Cisco Bug IDs: CSCvd40673.

A vulnerability in the Bidirectional Forwarding Detection (BFD) offload implementation of Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches could allow an unauthenticated, remote attacker to cause a crash of the iosd process, causing a denial of service (DoS) condition. The vulnerability is due to insufficient error handling when the BFD header in a BFD packet is incomplete. An attacker could exploit this vulnerability by sending a crafted BFD message to or across an affected switch. A successful exploit could allow the attacker to trigger a reload of the system. This vulnerability affects Catalyst 4500 Supervisor Engine 6-E (K5), Catalyst 4500 Supervisor Engine 6L-E (K10), Catalyst 4500 Supervisor Engine 7-E (K10), Catalyst 4500 Supervisor Engine 7L-E (K10), Catalyst 4500E Supervisor Engine 8-E (K10), Catalyst 4500E Supervisor Engine 8L-E (K10), Catalyst 4500E Supervisor Engine 9-E (K10), Catalyst 4500-X Series Switches (K10), Catalyst 4900M Switch (K5), Catalyst 4948E Ethernet Switch (K5). Cisco Bug IDs: CSCvc40729.

A vulnerability in the web-based user interface (web UI) of Cisco IOS XE Software could allow an authenticated, remote attacker to gain elevated privileges on an affected device. The vulnerability exists because the affected software does not reset the privilege level for each web UI session. An attacker who has valid credentials for an affected device could exploit this vulnerability by remotely accessing a VTY line to the device. A successful exploit could allow the attacker to access an affected device with the privileges of the user who previously logged in to the web UI. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software, if the HTTP Server feature is enabled and authentication, authorization, and accounting (AAA) authorization is not configured for EXEC sessions. The default state of the HTTP Server feature is version-dependent. This vulnerability was introduced in Cisco IOS XE Software Release 16.1.1. Cisco Bug IDs: CSCvf71769.

A vulnerability in the quality of service (QoS) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges. The vulnerability is due to incorrect bounds checking of certain values in packets that are destined for UDP port 18999 of an affected device. An attacker could exploit this vulnerability by sending malicious packets to an affected device. When the packets are processed, an exploitable buffer overflow condition may occur. A successful exploit could allow the attacker to execute arbitrary code on the affected device with elevated privileges. The attacker could also leverage this vulnerability to cause the device to reload, causing a temporary DoS condition while the device is reloading. The malicious packets must be destined to and processed by an affected device. Traffic transiting a device will not trigger the vulnerability. Cisco Bug IDs: CSCvf73881.

A vulnerability in Cisco IOS XE Software could allow an unauthenticated, remote attacker to log in to a device running an affected release of Cisco IOS XE Software with the default username and password that are used at initial boot, aka a Static Credential Vulnerability. The vulnerability is due to an undocumented user account with privilege level 15 that has a default username and password. An attacker could exploit this vulnerability by using this account to remotely connect to an affected device. A successful exploit could allow the attacker to log in to the device with privilege level 15 access. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software Release 16.x. This vulnerability does not affect Cisco IOS XE Software releases prior to Release 16.x. Cisco Bug IDs: CSCve89880.

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 Path Traversal vulnerability in the diagnostic shell for Cisco IOS and IOS XE Software could allow an authenticated, local attacker to use certain diagnostic shell commands that can overwrite system files. These system files may be sensitive and should not be able to be overwritten by a user of the diagnostic shell. The vulnerability is due to lack of proper input validation for certain diagnostic shell commands. An attacker could exploit this vulnerability by authenticating to the device, entering the diagnostic shell, and providing crafted user input to commands at the local diagnostic shell CLI. Successful exploitation could allow the attacker to overwrite system files that should be restricted. Cisco Bug IDs: CSCvg41950.

A vulnerability in the web framework code of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the web interface of the affected software. The vulnerability is due to insufficient input validation of some parameters that are passed to the web server of the affected software. An attacker could exploit this vulnerability by convincing a user of the web interface to access a malicious link or by intercepting a user request for the affected web interface and injecting malicious code into the request. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected web interface or allow the attacker to access sensitive browser-based information. Cisco Bug IDs: CSCvb09516.

A vulnerability in motherboard console ports of line cards for Cisco ASR 1000 Series Aggregation Services Routers and Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, physical attacker to access an affected device's operating system. The vulnerability exists because an engineering console port is available on the motherboard of the affected line cards. An attacker could exploit this vulnerability by physically connecting to the console port on the line card. A successful exploit could allow the attacker to gain full access to the affected device's operating system. This vulnerability affects only Cisco ASR 1000 Series Routers that have removable line cards and Cisco cBR-8 Converged Broadband Routers, if they are running certain Cisco IOS XE 3.16 through 16.5 releases. Cisco Bug IDs: CSCvc65866, CSCve77132.

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.

A vulnerability in the implementation of the Locator/ID Separation Protocol (LISP) in Cisco IOS XE 3.2 through 16.5 could allow an unauthenticated, remote attacker using an x tunnel router to bypass authentication checks performed when registering an Endpoint Identifier (EID) to a Routing Locator (RLOC) in the map server/map resolver (MS/MR). The vulnerability is due to a logic error introduced via a code regression for the affected software. An attacker could exploit this vulnerability by sending specific valid map-registration requests, which will be accepted by the MS/MR even if the authentication keys do not match, to the affected software. A successful exploit could allow the attacker to inject invalid mappings of EIDs to RLOCs in the MS/MR of the affected software. This vulnerability affects Cisco devices that are configured with LISP acting as an IPv4 or IPv6 map server. This vulnerability affects Cisco IOS XE Software release trains 3.9E and Everest 16.4. Cisco Bug IDs: CSCvc18008.

A vulnerability in the web-based user interface (web UI) of Cisco IOS XE 16.2 could allow an authenticated, remote attacker to elevate their privileges on an affected device. The vulnerability is due to incorrect default permission settings for new users who are created by using the web UI of the affected software. An attacker could exploit this vulnerability by using the web UI of the affected software to create a new user and then logging into the web UI as the newly created user. A successful exploit could allow the attacker to elevate their privileges on the affected device. This vulnerability affects Cisco devices that are running a vulnerable release Cisco IOS XE Software, if the HTTP Server feature is enabled for the device. The newly redesigned, web-based administration UI was introduced in the Denali 16.2 Release of Cisco IOS XE Software. This vulnerability does not affect the web-based administration UI in earlier releases of Cisco IOS XE Software. Cisco Bug IDs: CSCuy83062.

A vulnerability in the REST API of the web-based user interface (web UI) of Cisco IOS XE 3.1 through 16.5 could allow an unauthenticated, remote attacker to bypass authentication to the REST API of the web UI of the affected software. The vulnerability is due to insufficient input validation for the REST API of the affected software. An attacker could exploit this vulnerability by sending a malicious API request to an affected device. A successful exploit could allow the attacker to bypass authentication and gain access to the web UI of the affected software. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS XE Software, if the HTTP Server feature is enabled for the device. The newly redesigned, web-based administration UI was introduced in the Denali 16.2 Release of Cisco IOS XE Software. This vulnerability does not affect the web-based administration UI in earlier releases of Cisco IOS XE Software. Cisco Bug IDs: CSCuz46036.

A vulnerability in the Cisco Network Plug and Play application of Cisco IOS 12.4 through 15.6 and Cisco IOS XE 3.3 through 16.4 could allow an unauthenticated, remote attacker to gain unauthorized access to sensitive data by using an invalid certificate. The vulnerability is due to insufficient certificate validation by the affected software. An attacker could exploit this vulnerability by supplying a crafted certificate to an affected device. A successful exploit could allow the attacker to conduct man-in-the-middle attacks to decrypt confidential information on user connections to the affected software. Cisco Bug IDs: CSCvc33171.

A vulnerability in the web-based Wireless Controller GUI of Cisco IOS XE Software for Cisco 5760 Wireless LAN Controllers, Cisco Catalyst 4500E Supervisor Engine 8-E (Wireless) Switches, and Cisco New Generation Wireless Controllers (NGWC) 3850 could allow an authenticated, remote attacker to elevate their privileges on an affected device. The vulnerability is due to incomplete input validation of HTTP requests by the affected GUI, if the GUI connection state or protocol changes. An attacker could exploit this vulnerability by authenticating to the Wireless Controller GUI as a Lobby Administrator user of an affected device and subsequently changing the state or protocol for their connection to the GUI. A successful exploit could allow the attacker to elevate their privilege level to administrator and gain full control of the affected device. This vulnerability affects the following Cisco products if they are running Cisco IOS XE Software Release 3.7.0E, 3.7.1E, 3.7.2E, 3.7.3E, 3.7.4E, or 3.7.5E: Cisco 5760 Wireless LAN Controllers, Cisco Catalyst 4500E Supervisor Engine 8-E (Wireless) Switches, Cisco New Generation Wireless Controllers (NGWC) 3850. Cisco Bug IDs: CSCvd73746.