PT-2025-39299 · Cisco · Cisco Ios Xe+1

Published 2025-09-24 · Updated 2025-09-30 · CVE-2025-20311

Positive Technologies (AI Summary)

CVSS v3.1

7.4

High

Base vector

AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Cisco IOS XE Software for Catalyst 9000 Series Switches (affected versions not specified)

Description A flaw exists in how certain Ethernet frames are processed, potentially allowing a nearby, unauthenticated attacker to disrupt network traffic. Specifically, the issue can cause an outbound port to block all traffic, leading to a denial of service (DoS) condition. The root cause is improper handling of specially crafted Ethernet frames. An attacker can exploit this by sending these frames through an affected switch.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

DoS

Weakness Enumeration

CWE-19

Related Identifiers

BDU:2025-11735

CVE-2025-20311

Affected Products

Catalyst 9000 Series Switches

Cisco Ios Xe

References · 7

• https://bdu.fstec.ru/vul/2025-11735 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2025-20311 · Security Note
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cat9k-PtmD7bgy · Vendor Advisory
• https://t.me/CVEtracker/33260 · Telegram Post
• https://twitter.com/0dayPublishing/status/1973034789184647653 · Twitter Post
• https://twitter.com/CVEnew/status/1970996081761845746 · Twitter Post
• https://twitter.com/leftSECURE/status/1971300024782111038 · Twitter Post