CVE-2025-20134

Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL/TLS Certificate Denial of Service Vulnerability

Severity
High 8.6
CVSS 3.1
Exploited
Not listed
EPSS
0.004
32.6th percentile
Discovered by
Vendor
Published by the vendor
Published
Aug 14, 2025
Assigned by cisco

Description

A vulnerability in the certificate processing of 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 improper parsing of SSL/TLS certificates. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static Network Address Translation (NAT) rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Weakness: CWE-415

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