CVE-2024-20495 Denial of service in Cisco Adaptive Security Appliance (ASA) Software
Unauthenticated remote attackers can cause Cisco ASA or FTD devices to reload unexpectedly via crafted TLS key data, resulting in a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2024-20495?
CVE-2024-20495 is a high-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, published on 23 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the Remote Access VPN feature of 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 on an affected device. This vulnerability is due to improper validation of client key data after the TLS session is established. An attacker could exploit this vulnerability by sending a crafted key value to an affected system over the secure TLS session. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Weakness: CWE-20
Which versions are affected by CVE-2024-20495?
It affects 2 products.
Products include Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.
How do I fix CVE-2024-20495?
No fix has been published for CVE-2024-20495 yet. Limit exposure of the affected software until one is available.
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-2024-20495 being exploited?
There is no known exploitation of CVE-2024-20495 in the wild and no public exploit code.
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-2024-20353 Cisco ASA and FTD Denial of Service
- CVE-2016-6367 Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution
All Cisco Adaptive Security Appliance Software vulnerabilities
Sources
Also known as GHSA-5q5x-hwcj-q6c2.