Cisco IOS Xr

Format String vulnerability in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges on an affected device. Cisco Bug IDs: CSCvd73664.

Cisco IOS XR 4.3.4 through 5.3.0 on ASR 9000 devices, when uRPF, PBR, QoS, or an ACL is configured, does not properly handle bridge-group virtual interface (BVI) traffic, which allows remote attackers to cause a denial of service (chip and card hangs and reloads) by triggering use of a BVI interface for IPv4 packets, aka Bug ID CSCur62957.

Unspecified vulnerability in Cisco IOS 12.0 through 12.4, IOS XE 2.1.x through 2.3.x before 2.3.2, and IOS XR 3.2.x through 3.4.3, when Multiprotocol Label Switching (MPLS) and Label Distribution Protocol (LDP) are enabled, allows remote attackers to cause a denial of service (device reload or process restart) via a crafted LDP packet, aka Bug IDs CSCsz45567 and CSCsj25893.

Memory leak in Cisco IOS XR 5.1.x through 5.1.3, 5.2.x through 5.2.5, and 5.3.x through 5.3.2 on ASR 9001 devices allows remote attackers to cause a denial of service (control-plane protocol outage) via crafted fragmented packets, aka Bug ID CSCux26791.

Unspecified vulnerability in the sshd_child_handler process in the SSH server in Cisco IOS XR 3.4.1 through 3.7.0 allows remote attackers to cause a denial of service (process crash and memory consumption) via a crafted SSH2 packet, aka Bug ID CSCsu10574.

A vulnerability in the Event Management Service daemon (emsd) of Cisco IOS XR routers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. The vulnerability is due to improper handling of gRPC requests. An attacker could exploit this vulnerability by repeatedly sending unauthenticated gRPC requests to the affected device. A successful exploit could allow the attacker to crash the device in such a manner that manual intervention is required to recover. This vulnerability affects all Cisco IOS XR platforms that are running release 6.1.1 of Cisco IOS XR Software when the gRPC service is enabled on the device. The gRPC service is not enabled by default. Cisco Bug IDs: CSCvb14441.

Cisco IOS XR before 4.2.1 on ASR 9000 series devices and CRS series devices allows remote attackers to cause a denial of service (packet transmission outage) via a crafted packet, aka Bug IDs CSCty94537 and CSCtz62593.

Cisco IOS XR 5.x through 5.2.5 on NCS 6000 devices allows remote attackers to cause a denial of service (timer consumption and Route Processor reload) via crafted SSH traffic, aka Bug ID CSCux76819.

The NETIO and IPV4_IO processes in Cisco IOS XR 3.8 through 4.1, as used in Cisco Carrier Routing System and other products, allow remote attackers to cause a denial of service (CPU consumption) via crafted network traffic, aka Bug ID CSCti59888.

Unspecified vulnerability in Cisco IOS XR 4.1.x before 4.1.1 on Cisco Aggregation Services Routers (ASR) 9000 series devices allows remote attackers to cause a denial of service (line-card reload) via an IPv4 packet, aka Bug ID CSCtr26695.

The UDP process in Cisco IOS XR 4.3.1 does not free packet memory upon detecting full packet queues, which allows remote attackers to cause a denial of service (memory consumption) via UDP packets to listening ports, aka Bug ID CSCue69413.

Cisco IOS XR 3.9.x and 4.0.x before 4.0.3 and 4.1.x before 4.1.1, when an SPA interface processor is installed, allows remote attackers to cause a denial of service (device reload) via a crafted IPv4 packet, aka Bug ID CSCto45095.

Cisco IOS XR 3.8.3, 3.8.4, and 3.9.1 allows remote attackers to cause a denial of service (NetIO process restart or device reload) via a crafted IPv4 packet, aka Bug ID CSCth44147.

Cisco IOS XR 3.6.x, 3.8.x before 3.8.3, and 3.9.x before 3.9.1 does not properly remove sshd_lock files from /tmp/, which allows remote attackers to cause a denial of service (disk consumption) by making many SSHv1 connections, aka Bug ID CSCtd64417.

Cisco IOS XR Software Authenticated User Privilege Escalation Vulnerability

Cisco IOS XR Software for Cisco 8000 Series Routers and Network Convergence System 540 Series Routers Privilege Escalation Vulnerability

A vulnerability in Cisco IOS XR Software could allow an authenticated, local attacker to log in to the device with the privileges of the root user. More Information: CSCva38434. Known Affected Releases: 6.1.1.BASE.

Cisco IOS XR 6.1.1 allows local users to execute arbitrary OS commands as root by leveraging admin privileges, aka Bug ID CSCva38349.

The CLI in Cisco IOS XR 6.x through 6.0.1 allows local users to execute arbitrary OS commands in a privileged context by leveraging unspecified container access, aka Bug ID CSCuz62721.

Cisco IOS XR Software Command Injection Vulnerability

Cisco IOS XR Software Authenticated User Privilege Escalation Vulnerabilities

Cisco IOS XR Software Authenticated User Privilege Escalation Vulnerabilities

A vulnerability in the SSH client feature of Cisco IOS XR Software for Cisco 8000 Series Routers and Cisco Network Convergence System (NCS) 540 Series and 5700 Series Routers could allow an authenticated, local attacker to elevate privileges on an affected device. This vulnerability is due to insufficient validation of arguments that are included with the SSH client CLI command. An attacker with low-privileged access to an affected device could exploit this vulnerability by issuing a crafted SSH client command to the CLI. A successful exploit could allow the attacker to elevate privileges to root on the affected device.

A vulnerability in the iPXE boot function of Cisco IOS XR software could allow an authenticated, local attacker to install an unverified software image on an affected device. This vulnerability is due to insufficient image verification. An attacker could exploit this vulnerability by manipulating the boot parameters for image verification during the iPXE boot process on an affected device. A successful exploit could allow the attacker to boot an unverified software image on the affected device.

Cisco IOS XR Software Intermediate System–to–Intermediate System Denial of Service Vulnerability

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

The server IKEv1 implementation in Cisco IOS 12.2 through 12.4 and 15.0 through 15.6, IOS XE through 3.18S, IOS XR 4.3.x and 5.0.x through 5.2.x, and PIX before 7.0 allows remote attackers to obtain sensitive information from device memory via a Security Association (SA) negotiation request, aka Bug IDs CSCvb29204 and CSCvb36055 or BENIGNCERTAIN.

Cisco Network Convergence System 1000 Series TFTP Directory Traversal Vulnerability

Cisco IOS XR 3.4.0 through 3.9.1, when BGP is enabled, does not properly handle unrecognized transitive attributes, which allows remote attackers to cause a denial of service (peering reset) via a crafted prefix announcement, as demonstrated in the wild in August 2010 with attribute type code 99, aka Bug ID CSCti62211.

Cisco IOS XR Software Protocol Independent Multicast Denial of Service Vulnerability

Cisco IOS XR gRPC Software Denial of Service Vulnerability

A vulnerability in the gRPC code of Cisco IOS XR Software for Cisco Network Convergence System (NCS) 5500 Series Routers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition when the emsd service stops. The vulnerability is due to the software's inability to process HTTP/2 packets. An attacker could exploit this vulnerability by sending a malformed HTTP/2 frame to the affected device. A successful exploit could allow the attacker to create a DoS condition when the emsd service stops. Cisco Bug IDs: CSCvb99388.

Cisco IOS XR 4.2.0, 4.3.0, 5.0.0, 5.1.0, 5.2.0, 5.2.2, 5.2.4, 5.3.0, and 5.3.2 does not properly restrict the number of Path Computation Elements (PCEs) for OSPF LSA opaque area updates, which allows remote attackers to cause a denial of service (device reload) via a crafted update, aka Bug ID CSCuw83486.

Cisco IOS XR through 5.3.2 mishandles Local Packet Transport Services (LPTS) flow-base entries, which allows remote attackers to cause a denial of service (session drop) by making many connection attempts to open TCP ports, aka Bug ID CSCux95576.

A vulnerability in the HTTP 2.0 request handling code of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the Event Management Service daemon (emsd) to crash, resulting in a denial of service (DoS) condition. More Information: CSCvb14425. Known Affected Releases: 6.1.1.BASE. Known Fixed Releases: 6.1.2.6i.MGBL 6.1.22.9i.MGBL 6.2.1.14i.MGBL.

A vulnerability in Multicast Source Discovery Protocol (MSDP) ingress packet processing for Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the MSDP session to be unexpectedly reset, causing a short denial of service (DoS) condition. The MSDP session will restart within a few seconds. More Information: CSCvd94828. Known Affected Releases: 4.3.2.MCAST 6.0.2.BASE. Known Fixed Releases: 6.3.1.19i.MCAST 6.2.3.1i.MCAST 6.2.2.17i.MCAST 6.1.4.12i.MCAST.

Cisco IOS XR on ASR 9000 devices does not properly use compression for port-range and address-range encoding, which allows remote attackers to bypass intended Typhoon line-card ACL restrictions via transit traffic, aka Bug ID CSCup30133.

Cisco IOS XR Software DHCP Version 4 Server Denial of Service Vulnerability

Cisco IOS XR Software SNMP Management Plane Protection ACL Bypass Vulnerability

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 incomplete support for this feature. 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 ACL on the affected device. 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 .