CVE-2025-20316
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 access control list (ACL) programming of Cisco IOS XE Software for Cisco Catalyst 9500X and 9600X Series Switches could allow an unauthenticated, remote attacker to bypass a configured ACL on an affected device. This vulnerability is due to the flooding of traffic from an unlearned MAC address on a switch virtual interface (SVI) that has an egress ACL applied. An attacker could exploit this vulnerability by causing the VLAN to flush its MAC address table. This condition can also occur if the MAC address table is full. A successful exploit could allow the attacker to bypass an egress ACL on an affected device.
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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
EUVD
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
cisco ios_xe *
cisco catalyst_9600 *
cisco catalyst_9500 *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-284 The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the access control list (ACL) programming of Cisco IOS XE Software for Cisco Catalyst 9500X and 9600X Series Switches. It allows an unauthenticated, remote attacker to bypass a configured ACL by flooding traffic from an unlearned MAC address on a switch virtual interface (SVI) that has an egress ACL applied. The attacker can cause the VLAN to flush its MAC address table or exploit the condition when the MAC address table is full, enabling them to bypass the egress ACL on the device.


How can this vulnerability impact me? :

The vulnerability can allow an unauthenticated, remote attacker to bypass egress ACLs on affected Cisco switches. This means the attacker could send unauthorized traffic through the device, potentially leading to unauthorized access or data leakage within the network, undermining network security controls.


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