CVE-2025-20311
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-24

Last updated on: 2025-09-26

Assigner: Cisco Systems, Inc.

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.
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Meta Information
Published
2025-09-24
Last Modified
2025-09-26
Generated
2026-05-07
AI Q&A
2025-09-24
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
cisco catalyst_9000_series_switches *
cisco catalyst_9300_series_switches *
cisco catalyst_9500_series_switches *
cisco ios_xe 17.15.4
cisco catalyst_9200_series_switches *
cisco catalyst_9600_series_switches *
cisco meraki_ms390 *
cisco catalyst_9400_series_switches *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-19
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in Cisco IOS XE Software for Catalyst 9000 Series Switches where certain crafted Ethernet frames are improperly handled. An unauthenticated attacker who is adjacent to the network can send these specially crafted frames to the switch, causing the egress port to become blocked and drop all outbound traffic, leading to a denial of service (DoS) condition.


How can this vulnerability impact me? :

The impact of this vulnerability is a denial of service (DoS) condition on the affected switch's egress port. This means that the port will stop forwarding outbound traffic, potentially disrupting network connectivity and causing service outages for devices relying on that port.


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