CVE-2025-20241CWE-733

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

High · published August 27, 2025

CVSS v3.1
7.4
EPSS
0%
Percentile
18.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.4 · HIGH
Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00265 · 18.2th percentile
Weakness
CWE-733 · Compiler Optimization Removal or Modification of Security-critical Code
Published
2025-08-27T16:23Z
EPSS history
Timeline
  • 27 AUG 16:23Z
    Cisco Nexus 3000 and 9000 Series Switches IS-IS Protocol <TBD> Denial of Service Vulnerability
    cvelistv5