Description
A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly. This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and a denial of service (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.
Metrics
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco IOS XR Software | 7.8.1; 7.9.1; 7.10.1; 7.8.2; 7.8.22; 7.9.2; 7.11.1; 7.9.21; 7.10.2; 24.1.1; 7.11.2; 24.2.1; 24.1.2; 24.2.11; 24.3.1; 24.4.1; 24.2.2; 7.8.23; 7.11.21; 24.2.20 |
References
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzKMitigation, Vendor Advisory
Timeline
- Published
- Mar 11, 2026
- Last modified
- Jul 8, 2026
- NVD status
- Analyzed