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.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable yes

Technical Impact partial

Affected Vendors & Products

Vendors Products
Cisco
  • Adaptive Security Appliance Software
  • Firepower Threat Defense Software

No data.

No data.

References
Link Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-nat-dns-dos-bqhynHTM cve-icon cve-icon
History

Fri, 15 Aug 2025 08:15:00 +0000

Type Values Removed Values Added
First Time appeared Cisco
Cisco adaptive Security Appliance Software
Cisco firepower Threat Defense Software
Vendors & Products Cisco
Cisco adaptive Security Appliance Software
Cisco firepower Threat Defense Software

Thu, 14 Aug 2025 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Thu, 14 Aug 2025 16:45:00 +0000

Type Values Removed Values Added
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.
Title Cisco Adaptive Security Appliance and Firepower Threat Defense Software Network Address Translation DNS Inspection Denial of Service Vulnerability
Weaknesses CWE-835
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}
cve-icon MITRE

Status: PUBLISHED

Assigner: cisco

Published:

Updated: 2025-08-14T19:21:21.353Z

Reserved: 2024-10-10T19:15:13.213Z

Link: CVE-2025-20136

cve-icon Vulnrichment

Updated: 2025-08-14T18:41:23.750Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-08-14T17:15:35.063

Modified: 2025-08-15T13:12:51.217

Link: CVE-2025-20136

cve-icon Redhat

No data.