CVE-2024-20353 Cisco ASA and FTD Denial of Service
Unauthenticated remote attackers can cause Cisco ASA and FTD devices to reload unexpectedly via crafted HTTP requests, resulting in a denial of service.
- Exploited in the wild
- Since 24 Apr 2024
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2024-20353?
CVE-2024-20353 is a high-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, published on 24 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to incomplete error checking when parsing an HTTP header. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted web server on a device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.
Weakness: CWE-835
Which versions are affected by CVE-2024-20353?
It affects 2 products.
Products include Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.
How do I fix CVE-2024-20353?
No fix has been published for CVE-2024-20353 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 1 May 2024.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-20353 being exploited?
Yes. Attackers have exploited CVE-2024-20353 in the wild since at least 24 Apr 2024.
Other vulnerabilities in Cisco Adaptive Security Appliance Software
- CVE-2025-20333 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow
- 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-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-pp78-fggv-r899.