CVE-2025-20137 Security feature bypass in IOS
Remote attackers can bypass access control lists on Cisco Catalyst switches if IPv4 ACLs and IP Source Guard are configured together on the same interface.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-20137?
CVE-2025-20137 is a medium-severity vulnerability in Cisco Ios, published on 7 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability in the access control list (ACL) programming of Cisco IOS Software that is running on Cisco Catalyst 1000 Switches and Cisco Catalyst 2960L Switches could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to the use of both an IPv4 ACL and a dynamic ACL of IP Source Guard on the same interface, which is an unsupported configuration. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device. Note: Cisco documentation has been updated to reflect that this is an unsupported configuration. However, Cisco is publishing this advisory because the device will not prevent an administrator from configuring both features on the same interface. There are no plans to implement the ability to configure both features on the same interface on Cisco Catalyst 1000 or Catalyst 2960L Switches.
Weakness: CWE-284
Which versions are affected by CVE-2025-20137?
It affects 1 product.
Products include Cisco Ios.
How do I fix CVE-2025-20137?
No fix has been published for CVE-2025-20137 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-20137 being exploited?
There is no known exploitation of CVE-2025-20137 in the wild and no public exploit code.
Other vulnerabilities in Cisco Ios
- CVE-2017-12240 Cisco IOS and IOS XE Software DHCP Remote Code Execution
- CVE-2017-3881 Cisco IOS and IOS XE Remote Code Execution
- CVE-2018-0167 Cisco IOS, XR, and XE Software Buffer Overflow
- CVE-2017-6736 Cisco IOS and IOS XE Software SNMP Remote Code Execution
- CVE-2017-6737 Cisco IOS and IOS XE Software SNMP Remote Code Execution
Sources
Also known as GHSA-x37r-wqwh-97qm.