Cisco Catalyst 9500X/9600X ACL bypass via MAC flood
CVE-2025-20316 Published on September 24, 2025

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.

NVD

Vulnerability Analysis

CVE-2025-20316 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and no impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
LOW
Availability Impact:
NONE

Weakness Type

What is an Authorization Vulnerability?

The software does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

CVE-2025-20316 has been classified to as an Authorization vulnerability or weakness.


Products Associated with CVE-2025-20316

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Cisco IOS XE
 

Affected Versions

Cisco IOS XE Software:

Exploit Probability

EPSS
0.03%
Percentile
6.58%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.