CVE-2025-20136
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-08-14

Last updated on: 2025-08-15

Assigner: Cisco Systems, Inc.

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.
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Meta Information
Published
2025-08-14
Last Modified
2025-08-15
Generated
2026-05-07
AI Q&A
2025-08-14
EPSS Evaluated
2026-05-05
NVD
EUVD
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
cisco secure_firewall_threat_defense *
cisco secure_firewall_adaptive_security_appliance *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-835 The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the function that performs IPv4 and IPv6 Network Address Translation (NAT) DNS inspection on Cisco Secure Firewall ASA and FTD devices. It is caused by an infinite loop condition triggered when processing DNS packets with DNS inspection enabled and NAT44, NAT64, or NAT46 configured. An unauthenticated remote attacker can exploit this by sending specially crafted DNS packets that match a static NAT rule, causing the device to enter an infinite loop and reload unexpectedly.


How can this vulnerability impact me? :

Exploiting this vulnerability can cause the affected Cisco Secure Firewall ASA or FTD device to reload unexpectedly, resulting in a denial of service (DoS) condition. This means network traffic could be disrupted, potentially causing downtime and loss of availability for services protected by the device.


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