Buffer overflow in Cisco Firewall Threat Defense (FTD) and Cisco Adaptive Security Appliance (ASA) - CVE-2025-20333
Published: September 25, 2025 / Updated: April 1, 2026
Vulnerability identifier: #VU116119
CSH Severity: High
CVSS v4: 9.4 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H]
CVE-ID: CVE-2025-20333
CWE-ID: CWE-120
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerability details
The vulnerability allows a remote user to compromise the affected system.
The vulnerability exists due to a boundary error within the VPN Web Server when handling HTTP requests. A remote authenticated VPN user can send specially crafted HTTP requests to the affected device, trigger a buffer overflow and execute arbitrary code with root privileges.
Affected software
Cisco Firewall Threat Defense (FTD)
Cisco Adaptive Security Appliance (ASA)
Cisco Adaptive Security Appliance (ASA)
How to mitigate CVE-2025-20333
Install updates from vendor's website.
Cisco Firewall Threat Defense (FTD) - addressed in versions 7.0.8.1, 7.2.9, 7.4.2.4
Cisco Adaptive Security Appliance (ASA) - addressed in versions 9.16.4.85, 9.17.1.45, 9.18.4.47, 9.19.1.37, 9.20.3.7, 9.22.1.3
Cisco Adaptive Security Appliance (ASA) - addressed in versions 9.16.4.85, 9.17.1.45, 9.18.4.47, 9.19.1.37, 9.20.3.7, 9.22.1.3