CVE-2025-20136

High

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.

SeverityHigh
CVSS8.6
Exploit probability52. percentile0.7%
ProductCisco Adaptive Security Appliance (ASA) Software
PublishedAug 14, 2025
First seenAug 14, 2025
Weakness typeCWE-835CWE-835

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
Cisco Cisco Adaptive Security Appliance (ASA) Software9.12.3, 9.8.3, 9.12.1, 9.8.1, 9.12.2, 9.8.2.45, 9.8.2, 9.8.4, 9.14.1, 9.12.4, 9.8.2.26, 9.8.2.24, 9.8.2.15, 9.8.2.14, 9.8.2.35, 9.8.2.20, 9.8.2.8, 9.8.2.17, 9.8.2.28, 9.8.2.33, 9.8.2.38, 9.8.4.25, 9.12.3.2, 9.12.3.7, 9.8.3.18, 9.8.3.14, 9.8.4.15, 9.8.4.8, 9.8.1.7, 9.8.3.29, 9.14.1.10, 9.12.2.5, 9.8.4.22, 9.12.3.12, 9.8.4.7, 9.8.4.17, 9.8.3.16, 9.8.4.20, 9.8.3.11, 9.12.1.3, 9.8.4.3, 9.12.2.4, 9.8.4.12, 9.12.1.2, 9.8.3.26, 9.8.1.5, 9.12.2.9, 9.12.3.9, 9.8.3.21, 9.8.4.10, 9.12.2.1, 9.12.4.2, 9.14.1.6, 9.8.3.8, 9.14.1.15, 9.14.1.19, 9.8.4.26, 9.12.4.4, 9.14.1.30, 9.8.4.29, 9.12.4.7, 9.14.2, 9.12.4.8, 9.8.4.32, 9.12.4.10, 9.14.2.4, 9.14.2.8, 9.12.4.13, 9.8.4.33, 9.14.2.13, 9.8.4.34, 9.12.4.18, 9.8.4.35, 9.14.2.15, 9.12.4.24, 9.16.1, 9.8.4.39, 9.14.3, 9.12.4.26, 9.16.1.28, 9.14.3.1, 9.12.4.29, 9.14.3.9, 9.16.2, 9.12.4.30, 9.16.2.3, 9.8.4.40, 9.14.3.11, 9.12.4.35, 9.8.4.41, 9.15.1.1, 9.14.3.13, 9.16.2.7, 9.12.4.37, 9.14.3.15, 9.17.1, 9.16.2.11, 9.14.3.18, 9.16.2.13, 9.12.4.39, 9.12.4.38, 9.8.4.43, 9.14.4, 9.16.2.14, 9.17.1.7, 9.12.4.40, 9.16.3.3, 9.14.4.6, 9.16.3, 9.16.3.14, 9.17.1.9, 9.14.4.7, 9.12.4.41, 9.17.1.10, 9.8.4.44, 9.18.1, 9.12.4.47, 9.14.4.12, 9.16.3.15, 9.18.1.3, 9.17.1.11, 9.12.4.48, 9.14.4.13, 9.18.2, 9.16.3.19, 9.17.1.13, 9.12.4.50, 9.14.4.14, 9.17.1.15, 9.8.4.45, 9.12.4.52, 9.14.4.15, 9.16.3.23, 9.18.2.5, 9.16.4, 9.12.4.54, 9.14.4.17, 9.8.4.46, 9.17.1.20, 9.18.2.7, 9.19.1, 9.16.4.9, 9.12.4.55, 9.18.2.8, 9.14.4.22, 9.16.4.14, 9.8.4.48, 9.18.3, 9.19.1.5, 9.14.4.23, 9.12.4.56, 9.16.4.18, 9.17.1.30, 9.19.1.9, 9.18.3.39, 9.16.4.19, 9.12.4.58, 9.19.1.12, 9.18.3.46, 9.16.4.27, 9.19.1.18, 9.18.3.53, 9.18.3.55, 9.16.4.38, 9.17.1.33, 9.12.4.62, 9.16.4.39, 9.18.3.56, 9.20.1, 9.16.4.42, 9.19.1.22, 9.18.4, 9.20.1.5, 9.18.4.5, 9.19.1.24, 9.16.4.48, 9.18.4.8, 9.20.2, 9.19.1.27, 9.12.4.65, 9.16.4.55, 9.18.4.22, 9.20.2.10, 9.16.4.57, 9.19.1.28, 9.17.1.39, 9.12.4.67, 9.14.4.24, 9.18.4.24, 9.20.2.21, 9.16.4.61, 9.19.1.31, 9.18.4.29, 9.20.2.22, 9.16.4.62, 9.18.4.34, 9.20.3, 9.16.4.67, 9.16.4.70, 9.18.4.40—

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