CVE-2020-27124 Cisco Adaptive Security Appliance Software SSL/TLS Denial of Service Vulnerability
Unauthenticated remote attackers can cause Cisco ASA devices to reload unexpectedly via malicious SSL/TLS messages, 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-2020-27124?
CVE-2020-27124 is a high-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, published on 18 Nov 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the SSL/TLS handler of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause the affected device to reload unexpectedly, leading to a denial of service (DoS) condition. The vulnerability is due to improper error handling on established SSL/TLS connections. An attacker could exploit this vulnerability by establishing an SSL/TLS connection with the affected device and then sending a malicious SSL/TLS message within that connection. A successful exploit could allow the attacker to cause the device to reload.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Weakness: CWE-457
Which versions are affected by CVE-2020-27124?
It affects 1 product.
Products include Cisco Adaptive Security Appliance Software.
How do I fix CVE-2020-27124?
No fix has been published for CVE-2020-27124 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-2020-27124 being exploited?
There is no known exploitation of CVE-2020-27124 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-j69q-qfwm-m736.