CVE-2025-20316 Security feature bypass in Cisco IOS XE Software
An unauthenticated remote attacker can bypass egress ACLs on Cisco Catalyst switches by flooding traffic to flush the MAC address table.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-20316?
CVE-2025-20316 is a medium-severity vulnerability in Cisco IOS XE Software, published on 24 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-284
Which versions are affected by CVE-2025-20316?
How do I fix CVE-2025-20316?
No fix has been published for CVE-2025-20316 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-20316 being exploited?
There is no known exploitation of CVE-2025-20316 in the wild and no public exploit code.
Sources
Also known as GHSA-84gm-4jph-65cm.