Cisco Security Advisory
Cisco IOS XR Software Image Verification Bypass Vulnerability
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CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
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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.
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-ios-xr-verii-bypass-HhPwQRvxThis advisory is part of the March 2025 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: March 2025 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication.
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Vulnerable Products
This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco IOS XR Software, regardless of device configuration:
- 8000 Series Routers
- Network Convergence System (NCS) 540 Series Routers that are running NCS540L images
- NCS 1010
- NCS 1014
- NCS 5700 Series Fixed-Port Routers that are running NCS5700 images
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities.
Cisco has confirmed that this vulnerability does not affect the following Cisco products if they are running Cisco IOS XR Software:
- ASR 9000 Series Routers
- IOS XRd vRouter
- IOS XRv 9000 Routers
- NCS 540 Series Routers NCS540-ACC-SYS and NCS 540-24Z8Q2C-SYS
- NCS 5500 Series Routers
- NCS 5700 Series Fixed-Port Routers NCS-57C3-MOD-S and NCS-57C3-MOD-SE-S
Cisco has also confirmed that these vulnerabilities do not affect the following Cisco products:
- IOS Software
- IOS XE Software
- NX-OS Software
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There are no workarounds that address this vulnerability.
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Cisco has released free software updates that address the vulnerability described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.
Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.htmlAdditionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
In the following table, the left column lists Cisco software releases or trains. The right column indicates whether a release (train) is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability.
Cisco IOS XR Software Release First Fixed Release 7.10 and earlier Migrate to a fixed release. 7.11 7.11.21 24.2 24.2.2 24.3 24.3.2 24.4 24.4.1 Note: Cisco will not release SMUs to address this vulnerability.
The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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This vulnerability was found during internal security testing.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Version Description Section Status Date 1.0 Initial public release. - Final 2025-MAR-12
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