CVE-2025-20136

Cisco Adaptive Security Appliance and Firepower Threat Defense Software Network Address Translation DNS Inspection Denial of Service Vulnerability

Severity
High 8.6
CVSS 3.1
Exploited
Not listed
EPSS
0.006
45.7th percentile
Discovered by
Vendor
Published by the vendor
Published
Aug 14, 2025
Assigned by cisco

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) Firewall / NGFW cna-assigner
Cisco Cisco Firepower Threat Defense (FTD) Firewall / NGFW cna-assigner
Vendor-reported affected versions (2)
  • Cisco · Cisco Adaptive Security Appliance (ASA) Software
  • Cisco · Cisco Firepower Threat Defense Software