Vulnerability · Published Aug 14, 2025 · Assigned by cisco
CVE-2025-20135Cisco Adaptive Security Appliance and Firepower Threat Defense Software DHCP Denial of Service Vulnerability
Medium 4.3
In plain English
A medium-severity memory leak in Cisco Adaptive Security Appliance (ASA) Software from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco Adaptive Security Appliance (ASA) Software | 9.12.39.8.39.12.19.8.19.12.29.8.2.459.8.29.8.4 |
| Cisco | Cisco Firepower Threat Defense Software | 6.2.3.146.4.0.16.2.3.76.2.36.4.0.26.2.3.96.2.3.16.2.3.2 |
Weakness: CWE-401 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L