CVE-2025-20134
Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL/TLS Certificate Denial of Service Vulnerability
Description
A vulnerability in the certificate processing of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper parsing of SSL/TLS certificates. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static Network Address Translation (NAT) rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Weakness: CWE-415
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-ssltls-dos-eHw76vZe
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software SSL/TLS Certificate Denial of Service Vulnerability
Cisco’s rating: High (advisory CVSS 8.6) · Published Aug 14, 2025 · updated Aug 19, 2025 (revision 1.1)
Bug ID: CSCwk44159
The vendor’s rating applies to the whole advisory and can differ from this CVE’s own CVSS severity. Where this comes from