—–BEGIN PGP SIGNED MESSAGE—–

Hash: SHA256

Denial of Service Vulnerability in CISCO 

Indian – Computer Emergency Response Team (https://www.cert-in.org.in)

Severity Rating: HIGH

Component Affected

Catalyst 9200 Series Switches

Catalyst 9300 Series Switches

Catalyst 9400 Series Switches

Catalyst 9500 Series Switches

Catalyst 9600 Series Switches

Overview

A vulnerability has been reported 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.

Target Audience: 

All IT administrators and individuals responsible for maintaining and updating in Cisco IOS XE Software.

Risk Assessment:

High risk of data manipulation and service disruption.

Impact Assessment:

Potential impact on confidentiality, integrity, and availability of the system.

Description

This vulnerability exists due to improper handling of crafted Ethernet frames. An attacker could exploit this vulnerability by sending crafted Ethernet frames through an affected switch.

Successful exploitation of this vulnerability 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.

Solution

Apply appropriate updates as mentioned in Cisco Advisory

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cat9k-PtmD7bgy

Vendor Information

CISCO

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cat9k-PtmD7bgy

References

CISCO

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cat9k-PtmD7bgy

CVE Name

CVE-2025-20311

– —

Thanks and Regards,

CERT-In

Incident Response Help Desk

e-mail: incident@cert-in.org.in

Phone: +91-11-22902657

Toll Free Number: 1800-11-4949

Toll Free Fax : 1800-11-6969

Web: http://www.cert-in.org.in

PGP Fingerprint: A768 083E 4475 5725 B81A A379 2156 C0C0 B620 D0B4

PGP Key information:

https://www.cert-in.org.in/s2cMainServlet?pageid=CONTACTUS

Postal address:

Indian Computer Emergency Response Team (CERT-In)

Ministry of Electronics and Information Technology

Government of India

Electronics Niketan

6, C.G.O. Complex

New Delhi-110 003

—–BEGIN PGP SIGNATURE—–

iQIzBAEBCAAdFiEE6r4Iam/Ey0c/KakL3jCgcSdcys8FAmjWnfkACgkQ3jCgcSdc

ys+4zA//TH5hX0RwO0u05eotztruQfiQHjMvTkWoQiQgdY+Raca/ALaq73XL5WM0

Z09/VV9MXmx23K3D1BOlnAqHcmEeVtFOFlp89Z6RZq1IQMNLznQR94hLCHRmjqx/

u4+ycXfVd3DGpO521fG5ydeg90J/G9UXRhBHyzFZyUlkrp9BwYzu6Ml1kYh+5tvp

yLZCq79NHP3A7seyDMFL3ux4Njj3FZXrY9tQ7Sf8Vd6Z9xjoq8QbzGcomi6dfEHf

GHt9Dw/WIG3uQly77YigK2oY9JXzGXrj/KyqZYcsGLCHuVrAvhNOebe9mI/yl88f

59MCgdfi70duKnCj8wsZBpFthj+jvVCLsNKgUh8ZW/MpTFl/lCdDbDvTjekSiIis

FHyDTn8/RxQevv7nKSPOayaP7JpWU1dyNlYrwx2KZx5fFJ+GgQtfrv5iY+mNa+x2

SvAJ3sbhptdRy0XjuUJJ2XeXRvf34T4lhMh6vR71oxrrnFoJp9oNaMUi2fmMMjBA

GMHZU6D2kcs+Dy3VFZLr2znQMPuJeYsjI809bqEJgTxmIF76tvq3liDDWdvt9am5

AVJKQm7hmyuZQkl6yuyGCrg6pJnE2AFDpEOZWXsC0bzGSzKygDSnAdVLTeeiUzeH

eRIJnUSqhu4wORNS58YHr8QVXIZeAa+krwJBPHCGoIjsCpgmMcw=

=pr9c

—–END PGP SIGNATURE—–