Secure Firewall ASA and FTD
CVE-2025-20133: Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Authentication Targeted Denial of Service Vulnerability
A vulnerability in the management and VPN web servers of the Remote Access SSL VPN feature of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to unexpectedly stop responding, resulting in a DoS condition.
Published
ExploitedNot in CISA KEV
Ransomware useNot reportedPer CISA
SeverityHIGHCVSS 3.1 8.6
EPSS0.78%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 Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.15 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | 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 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.18 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.8 | 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 9.14 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | 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 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | 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 9.16 | 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 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | 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 9.16 | 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 9.16 | 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 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.16 | 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 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.12 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.14 | 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 9.16 | 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 9.16 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.20 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.17 | See the advisory |
| Cisco Adaptive Security Appliance (ASA) Software 9.19 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 7.1 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 6.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.1 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 7.1 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.3 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 7.3 | See the advisory |
| Cisco Firepower Threat Defense Software 7.1 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | 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 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.0 | See the advisory |
| Cisco Firepower Threat Defense Software 7.4 | See the advisory |
| Cisco Firepower Threat Defense Software 6.6 | See the advisory |
| Cisco Firepower Threat Defense Software 6.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.3 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | See the advisory |
| Cisco Firepower Threat Defense Software 7.4 | See the advisory |
| Cisco Firepower Threat Defense Software 7.2 | 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 management and VPN web servers of the Remote Access SSL VPN feature of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to unexpectedly stop responding, resulting in a DoS condition.
This vulnerability is due to ineffective validation of user-supplied input during the Remote Access SSL VPN authentication process. An attacker could exploit this vulnerability by sending a crafted request to the VPN service on an affected device. A successful exploit could allow the attacker to cause a DoS condition where the device stops responding to Remote Access SSL VPN authentication requests.
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.