Secure Firewall ASA and FTD
CVE-2025-20219: Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Access Control 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.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.22 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.22 | See the advisory |
| Cisco Firepower Threat Defense Software 7.3 | See the advisory |
| Cisco Firepower Threat Defense Software 7.3 | See the advisory |
| Cisco Firepower Threat Defense Software 7.3 | See the advisory |
| Cisco Firepower Threat Defense Software 7.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.3 | See the advisory |
| Cisco Firepower Threat Defense Software 7.6 | See the advisory |
| Cisco Firepower Threat Defense Software 7.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.4 | See the advisory |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
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.
Exploitation
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 11 Oct 2026.