PT-2025-33315 · Cisco · Cisco Secure Firewall Asa+2

Jason Crowder · Published 2025-08-14 · Updated 2025-08-15 · CVE-2025-20136

Positive Technologies (AI Summary)

CVSS v3.1

8.6

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software (affected versions not specified)

Description: A vulnerability in the function that performs IPv4 and IPv6 Network Address Translation (NAT) DNS inspection could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This issue is due to an infinite loop condition that occurs when a device processes DNS packets with DNS inspection enabled and is configured for NAT44, NAT64, or NAT46. An attacker could exploit this by sending crafted DNS packets that match a static NAT rule with DNS inspection enabled. A successful exploit could allow the attacker to create an infinite loop and cause the device to reload, resulting in a DoS condition.

Recommendations: At the moment, there is no information about a newer version that contains a fix for this vulnerability.

DoS

Infinite Loop

Weakness Enumeration

CWE-835

Related Identifiers

BDU:2025-10340

CVE-2025-20136

Affected Products

Cisco Asa

Cisco Secure Firewall Asa

Cisco Secure Firewall Threat Defense

References · 7

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-nat-dns-dos-bqhynHTM · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-20136 · Security Note
• https://bdu.fstec.ru/vul/2025-10340 · Security Note
• https://twitter.com/CveFindCom/status/1956041281089499366 · Twitter Post
• https://twitter.com/0dayPublishing/status/1956045535241961488 · Twitter Post
• https://twitter.com/CVEnew/status/1956390341352833416 · Twitter Post
• https://t.me/true_secator/7332 · Telegram Post