Secure Firewall ASA and FTD
CVE-2026-20103: A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appli…
A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust device memory resulting in a denial of service (DoS) condition to new Remote Access SSL VPN connections.
Published
ExploitedNot in CISA KEV
Ransomware useNot reportedPer CISA
SeverityHIGHCVSS 3.1 8.6
EPSS0.36%Chance of exploitation in 30 days
Public exploitNot tracked
FixNot yet
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 Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.23 | See the advisory |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.23 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 6.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 6.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 6.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.0 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.1 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.6 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.6 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.6 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.6 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.7 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.7 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.7 | See the advisory |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust device memory resulting in a denial of service (DoS) condition to new Remote Access SSL VPN connections. This does not affect the management interface, though it may become temporarily unresponsive. This vulnerability is due to trusting user input without validation. An attacker could exploit this vulnerability by sending crafted packets to the Remote Access SSL VPN server. A successful exploit could allow the attacker to cause the device web interface to stop responding, resulting in a DoS condition.
Exploitation
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 11 Oct 2026.