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.
CVSS Score
6.7
EPSS Score
0.0
Published
2025-03-12
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.
CVSS Score
7.4
EPSS Score
0.001
Published
2024-09-11
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.
CVSS Score
5.3
EPSS Score
0.002
Published
2024-09-11
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.
CVSS Score
7.4
EPSS Score
0.001
Published
2024-03-13
CVE-2023-44487
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.
Known exploited
CVSS Score
7.5
EPSS Score
0.944
Published
2023-10-10
A vulnerability in Cisco IOS XR Software image verification checks could allow an authenticated, local attacker to execute arbitrary code on the underlying operating system.
This vulnerability is due to a time-of-check, time-of-use (TOCTOU) race condition when an install query regarding an ISO image is performed during an install operation that uses an ISO image. An attacker could exploit this vulnerability by modifying an ISO image and then carrying out install requests in parallel. A successful exploit could allow the attacker to execute arbitrary code on an affected device.
CVSS Score
5.7
EPSS Score
0.0
Published
2023-09-13
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 .
CVSS Score
5.8
EPSS Score
0.0
Published
2023-09-13
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.
CVSS Score
6.7
EPSS Score
0.0
Published
2023-09-13
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.
CVSS Score
4.6
EPSS Score
0.001
Published
2023-03-09
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.
CVSS Score
7.4
EPSS Score
0.002
Published
2021-09-23
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