Cisco IOS XR Software Security Hardening Release: September 2026

There are no workarounds that address these vulnerabilities.

To remediate these vulnerabilities and avoid future exposure as described in this advisory, Cisco strongly recommends that customers upgrade to the fixed software indicated in this advisory.

Fixed Releases

In the following table, the left column lists the affected Cisco IOS XR Software train, and the right column lists the first release that includes the fixes for these vulnerabilities, and the releases that have SMUs for affected platforms to address these vulnerabilities.

Customers are advised upgrade to a fixed release. If a fixed release is not available, do the following based on the table:

1. Upgrade to a release that has available SMUs.

2. Apply the appropriate SMUs for the upgraded release.

There may be approximately 16 SMUs available for each release to mitigate the vulnerabilities that are covered by the CWEs in this advisory. Cisco IOS XR Software releases 26.2.2 and 26.3.1 are the first fixed releases that contain fixes for the vulnerabilities that are described in this advisory.

1. SMUs for Release 7.3.2 are available only for the optical platform Cisco Network Convergence System (NCS) 1002.

2. SMUs for Release 25.4.1 are available only for the optical platforms Cisco NCS 1001, Cisco NCS 1004, and Cisco NCS 1010.

For more information on finding which SMUs may have been published for these vulnerabilities, see the Download SMUs from Cisco.com section of Understand Cisco IOS XR Software Maintenance Updates (SMUs).

In the following table, the left column lists the affected Cisco IOS XR Software functional areas, the middle column lists affected releases and platforms, and the right column the right column indicates whether a functional area is affected by this vulnerability and lists the SMU identifier that can be used to locate the the appropriate SMU.

For example, the SMU for Release 24.2.2 for Cisco IOS XRv 9000 Routers BGP would be named xrv9k-24.2.2.CSCwu14807.tar.

Note: SMU identifiers are unique identifiers, not Cisco Bug IDs. All SMUs may not be applicable to all releases and platforms.

1. Platforms that run Cisco IOS XR7 (LNT) Software include Cisco 8000 Series Routers, Cisco NCS 1010, Cisco NCS 540L Routers, and Cisco NCS 5700 Series regardless of optional features installed. To determine whether a device is running Cisco IOS XR7 (LNT) Software using the CLI, see the Vulnerable Products section of this advisory.

2. CSCwv19171 applies to both IS-IS and OSPF.

3. For release train 7.10.2 only, SMU Identifier CSCwv19181 supersedes CSCwv40753. For all other release trains, SMU Identifier CSCwv40753 supersedes CSCwv19181.

4. SMU Identifier CSCwv40741 supersedes CSCwv19174.

5. SMU Identifier CSCwu13268 supersedes CSCwv19178.

6. SMU Identifier CSCwv36143 supersedes CSCwu14817.

The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.