Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Access Control Rules Bypass Vulnerability
A vulnerability in the implementation of access control rules for loopback interfaces in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to send traffic that should have been blocked to a loopback interface.<br><br>
This vulnerability is due to improper enforcement of access control rules for loopback interfaces. An attacker could exploit this vulnerability by sending traffic to a loopback interface on an affected device. A successful exploit could allow the attacker to bypass configured access control rules and send traffic that should have been blocked to a loopback interface on the device.<br><br>
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.<br><br>
This advisory is available at the following link:<br><a href=”https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-acl-bypass-mtPze9Yh”>https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-acl-bypass-mtPze9Yh</a><br><br>
This advisory is part of the August 2025 release of the Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see <a href=”https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75415″>Cisco Event Response: August 2025 Semiannual Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication</a>.<br><br>
<br/>Security Impact Rating: Medium
<br/>CVE: CVE-2025-20219Cisco Security AdvisoryRead More