CVE-2025-20241

Cisco Nexus 3000 and 9000 Series Switches IS-IS Protocol <TBD> Denial of Service Vulnerability

Severity
High 7.4
CVSS 3.1
Exploited
Not listed
EPSS
0.003
18.6th percentile
Discovered by
Vendor
Published by the vendor
Published
Aug 27, 2025
Assigned by cisco

Description

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) feature of Cisco NX-OS Software for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the IS-IS process to unexpectedly restart, which could cause an affected device to reload. 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. A successful exploit could allow the attacker to cause the unexpected restart of the IS-IS process, which could 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.

Weakness: CWE-733

Affected products

Vendor Product Category Matched by
Cisco Cisco NX-OS Software Routing & Switching cna-assigner
Vendor-reported affected versions (1)
  • Cisco · Cisco NX-OS Software