CVE-2025-20244
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access VPN Web Server Denial of Service Vulnerability
Description
A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow a remote attacker that is authenticated as a VPN user to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to incomplete error checking when parsing an HTTP header field value. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause a DoS condition, which would cause the affected device to reload.
Weakness: CWE-1287
Affected products
| Vendor | Product | Category | Matched by |
|---|---|---|---|
| Cisco | Cisco Adaptive Security Appliance (ASA) Check your version | Firewall / NGFW | cna-assigner |
| Cisco | Cisco Firepower Threat Defense (FTD) Check your version | Firewall / NGFW | cna-assigner |
Vendor-reported products (2)
- Cisco · Cisco Adaptive Security Appliance (ASA) Software
- Cisco · Cisco Firepower Threat Defense Software
Vendor advisory
cisco-sa-asaftd-vpnwebs-dos-hjBhmBsX
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access VPN Web Server Denial of Service Vulnerability
Cisco’s rating: High (advisory CVSS 7.7) · Published Aug 14, 2025
Bug ID: CSCwo08017
The vendor’s rating applies to the whole advisory and can differ from this CVE’s own CVSS severity. Where this comes from