CVE-2025-20333 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow
Authenticated remote attackers can execute arbitrary code as root on Cisco ASA and FTD devices via crafted HTTP requests, leading to full device compromise.
- Exploited in the wild
- Since 25 Sep 2025
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-20333?
CVE-2025-20333 is a critical code injection vulnerability in Cisco Adaptive Security Appliance Software, published on 25 Sep 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker with valid VPN user credentials could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as root, possibly resulting in the complete compromise of the affected device.
Weakness: CWE-120
Which versions are affected by CVE-2025-20333?
It affects 2 products.
Products include Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.
How do I fix CVE-2025-20333?
No fix has been published for CVE-2025-20333 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 26 Sep 2025.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2025-20333 being exploited?
Yes. Attackers have exploited CVE-2025-20333 in the wild since at least 25 Sep 2025.
Public exploit code: 3 proofs of concept on GitHub.
Other vulnerabilities in Cisco Adaptive Security Appliance Software
- CVE-2016-6366 Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow
- CVE-2026-20349 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection
- CVE-2024-20353 Cisco ASA and FTD Denial of Service
- CVE-2016-6367 Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution
- CVE-2020-3452 Cisco ASA and FTD Read-Only Path Traversal
All Cisco Adaptive Security Appliance Software vulnerabilities
Sources
Also known as GHSA-vg93-6w2x-3cvp.