CVE-2025-20311

Published Sep 24, 2025

Last updated 25 days ago

Overview

Description
A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated, adjacent attacker to cause an egress port to become blocked and drop all outbound traffic. This vulnerability is due to improper handling of crafted Ethernet frames. An attacker could exploit this vulnerability by sending crafted Ethernet frames through an affected switch. A successful exploit could allow the attacker to cause the egress port to which the crafted frame is forwarded to start dropping all frames, resulting in a denial of service (DoS) condition.
Source
psirt@cisco.com
NVD status
Analyzed
Products
ios_xe

Risk scores

CVSS 3.1

Type
Secondary
Base score
7.4
Impact score
4
Exploitability score
2.8
Vector string
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Severity
HIGH

Weaknesses

psirt@cisco.com
CWE-19

Social media

Hype score
Not currently trending

Configurations