A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE 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 when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in 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 have formed an adjacency.

Cisco Systems, Inc. AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Cisco Systems, Inc. CWE-476

Cisco Systems, Inc. https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-sGjyOUHX [No types assigned]