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Cisco IOS XE Software on Cisco Catalyst 9500X and 9600X Series Switches Virtual Interface Access Control List Bypass Vulnerability

cisco-sa-cat9k-acl-L4K7VXgD · Medium · Published · Updated

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. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cat9k-acl-L4K7VXgD This advisory is part of the September 2025 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2025 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.

Cisco advisory · CSAF JSON

Workarounds

There is a workaround that addresses this vulnerability. Egress ACLs can be converted to ingress ACLs. However, depending on how many interfaces are configured with egress ACLs, the configuration changes required could be extensive.

While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

CVEsCVE-2025-20316
Cisco Bug IDsCSCwo11541
CVSS ScoreBase 5.3
Base 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:X/RL:X/RC:X
Product Names From Source
Cisco IOS XE Software 17.7.1, Cisco IOS XE Software 17.10.1, Cisco IOS XE Software 17.10.1b, Cisco IOS XE Software 17.8.1, Cisco IOS XE Software 17.9.1, Cisco IOS XE Software 17.9.2, Cisco IOS XE Software 17.9.3, Cisco IOS XE Software 17.9.4, Cisco IOS XE Software 17.9.5, Cisco IOS XE Software 17.9.4a, Cisco IOS XE Software 17.9.6, Cisco IOS XE Software 17.9.6a, Cisco IOS XE Software 17.9.6b, Cisco IOS XE Software 17.9.7, Cisco IOS XE Software 17.11.1, Cisco IOS XE Software 17.12.1, Cisco IOS XE Software 17.12.2, Cisco IOS XE Software 17.12.3, Cisco IOS XE Software 17.12.4, Cisco IOS XE Software 17.12.5, Cisco IOS XE Software 17.13.1, Cisco IOS XE Software 17.14.1, Cisco IOS XE Software 17.15.1, Cisco IOS XE Software 17.15.2, Cisco IOS XE Software 17.15.3, Cisco IOS XE Software 17.15.2b, Cisco IOS XE Software 17.16.1, Cisco IOS XE Software 17.17.1, Cisco IOS XE Software 17.18.0EFT, Cisco IOS, Cisco IOS XE Software

Related Products

Product CVE Evidence
Cisco Catalyst 9500 Series Switches CVE-2025-20316 Cisco OpenVuln
Cisco IOS CVE-2025-20316 Cisco OpenVuln
Cisco IOS XE Software CVE-2025-20316 Cisco OpenVuln
Cisco Catalyst 9600 Series Switches CVE-2025-20316 Cisco OpenVuln · software-dependent
Cisco Catalyst 9400 Series Switches CVE-2025-20316 Cisco OpenVuln · software-dependent
Cisco Catalyst 9200 Series Switches CVE-2025-20316 Cisco OpenVuln · software-dependent
Cisco Catalyst 9300 Series Switches CVE-2025-20316 Cisco OpenVuln · software-dependent