CVE-2025-20136
Cisco Adaptive Security Appliance and Firepower Threat Defense Software Network Address Translation DNS Inspection Denial of Service Vulnerability
Description
A vulnerability in the function that performs IPv4 and IPv6 Network Address Translation (NAT) DNS inspection for 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 an infinite loop condition that occurs when a Cisco Secure ASA or Cisco Secure FTD device processes DNS packets with DNS inspection enabled and the device is configured for NAT44, NAT64, or NAT46. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static NAT rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to create an infinite loop and cause the device to reload, resulting in a DoS condition.
Weakness: CWE-835
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-nat-dns-dos-bqhynHTM
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Network Address Translation DNS Inspection Denial of Service Vulnerability
Cisco’s rating: High (advisory CVSS 8.6) · Published Aug 14, 2025
Bug IDs: CSCwm08231 , CSCwm08232
The vendor’s rating applies to the whole advisory and can differ from this CVE’s own CVSS severity. Where this comes from