CVE-2025-20135

Cisco Adaptive Security Appliance and Firepower Threat Defense Software DHCP Denial of Service Vulnerability

Severity
Medium 4.3
CVSS 3.1
Exploited
Not listed
EPSS
0.002
9.9th percentile
Discovered by
Vendor
Published by the vendor
Published
Aug 14, 2025
Assigned by cisco

Description

A vulnerability in the DHCP client functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to exhaust available memory. This vulnerability is due to improper validation of incoming DHCP packets. An attacker could exploit this vulnerability by repeatedly sending crafted DHCPv4 packets to an affected device. A successful exploit could allow the attacker to exhaust available memory, which would affect availability of services and prevent new processes from starting, resulting in a Denial of Service (DoS) condition that would require a manual reboot. Note: On Cisco Secure FTD Software, this vulnerability does not affect management interfaces.

Weakness: CWE-401

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