A vulnerability in the boot process of Cisco IOS XR Software could allow an authenticated, local attacker to bypass Cisco IOS XR image signature verification and load unverified software on an affected device. To exploit this vulnerability, the attacker must have root-system privileges on the affected device.
This vulnerability is due to incomplete validation of files in the boot verification process. An attacker could exploit this vulnerability by manipulating the system configuration options to bypass some of the integrity checks that are performed during the boot process. A successful exploit could allow the attacker to control the boot configuration, which could enable them to bypass the requirement to run Cisco-signed images or alter the security properties of the running system.
Note: Because exploitation of this vulnerability could result in the attacker bypassing Cisco image verification, Cisco has raised the Security Impact Rating (SIR) of this advisory from Medium to High.
A vulnerability in the segment routing feature for the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.
This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending specific IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process on all affected devices that are participating in the Flexible Algorithm to crash and restart, resulting in a 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. This vulnerability affects segment routing for IS-IS over IPv4 and IPv6 control planes as well as devices that are configured as level 1, level 2, or multi-level routing IS-IS type.
A vulnerability in the Dedicated XML Agent feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) on XML TCP listen port 38751.
This vulnerability is due to a lack of proper error validation of ingress XML packets. An attacker could exploit this vulnerability by sending a sustained, crafted stream of XML traffic to a targeted device. A successful exploit could allow the attacker to cause XML TCP port 38751 to become unreachable while the attack traffic persists.
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 PPP over Ethernet (PPPoE) termination feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to crash the ppp_ma process, resulting in a denial of service (DoS) condition.
This vulnerability is due to the improper handling of malformed PPPoE packets that are received on a router that is running Broadband Network Gateway (BNG) functionality with PPPoE termination on a Lightspeed-based or Lightspeed-Plus-based line card. An attacker could exploit this vulnerability by sending a crafted PPPoE packet to an affected line card interface that does not terminate PPPoE. A successful exploit could allow the attacker to crash the ppp_ma process, resulting in a DoS condition for PPPoE traffic across the router.
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.
A vulnerability in the GRand Unified Bootloader (GRUB) for Cisco IOS XR Software could allow an unauthenticated attacker with physical access to the device to view sensitive files on the console using the GRUB bootloader command line. This vulnerability is due to the inclusion of unnecessary commands within the GRUB environment that allow sensitive files to be viewed. An attacker could exploit this vulnerability by being connected to the console port of the Cisco IOS XR device when the device is power-cycled. A successful exploit could allow the attacker to view sensitive files that could be used to conduct additional attacks against the device.
A vulnerability in the Unidirectional Link Detection (UDLD) feature of Cisco FXOS Software, Cisco IOS Software, Cisco IOS XE Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload. This vulnerability is due to improper input validation of the UDLD packets. An attacker could exploit this vulnerability by sending specifically crafted UDLD packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: The UDLD feature is disabled by default, and the conditions to exploit this vulnerability are strict. An attacker must have full control of a directly connected device. On Cisco IOS XR devices, the impact is limited to the reload of the UDLD process.
A vulnerability in the Topology Discovery Service of Cisco One Platform Kit (onePK) in Cisco IOS Software, Cisco IOS XE Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient length restrictions when the onePK Topology Discovery Service parses Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol message to an affected device. An exploit could allow the attacker to cause a stack overflow, which could allow the attacker to execute arbitrary code with administrative privileges, or to cause a process crash, which could result in a reload of the device and cause a DoS condition.
The SNMPv2 implementation in Cisco IOS XR allows remote authenticated users to cause a denial of service (snmpd daemon reload) via a malformed SNMP packet, aka Bug ID CSCur25858.