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
18.7th percentile
Discovered by
Vendor
Vendor-published field
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 products (1)
  • Cisco · Cisco NX-OS Software

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