CVE-2025-20133

Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Authentication Targeted Denial of Service Vulnerability

Severity
High 8.6
CVSS 3.1
Exploited
Not listed
EPSS
0.007
51.3th percentile
Discovered by
Vendor
Published by the vendor
Published
Aug 14, 2025
Assigned by cisco

Description

A vulnerability in the management and VPN web servers of the Remote Access SSL VPN feature of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to unexpectedly stop responding, resulting in a DoS condition. This vulnerability is due to ineffective validation of user-supplied input during the Remote Access SSL VPN authentication process. An attacker could exploit this vulnerability by sending a crafted request to the VPN service on an affected device. A successful exploit could allow the attacker to cause a DoS condition where the device stops responding to Remote Access SSL VPN authentication requests.

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