What’s Vulnerable › Vulnerabilities
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
- Severity: high (CVSS 8.6 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.8% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2025-08-14 · updated 2026-06-17
- Weakness: CWE-401
Description
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.
Affected products
- Cisco ASA Software: 9.12.3, 9.8.3, 9.12.1, 9.12.2, 9.8.2.45, 9.8.4 (+183)
- Cisco Firepower Threat Defense Software: 6.2.3.14, 6.4.0.1, 6.2.3.7, 6.4.0.2, 6.2.3.9, 6.2.3.1 (+81)
References
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