CVE-2024-20331 Cisco Adaptive Security Appliance and Firepower Threat Defense Software VPN Authentication DoS Vulnerability
An unauthenticated remote attacker can disrupt Remote Access SSL VPN sessions by exploiting insufficient entropy in authentication handles, preventing legitimate user access.
- 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-2024-20331?
CVE-2024-20331 is a medium-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 session authentication functionality of the Remote Access SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to prevent users from authenticating. This vulnerability is due to insufficient entropy in the authentication process. An attacker could exploit this vulnerability by determining the handle of an authenticating user and using it to terminate their authentication session. A successful exploit could allow the attacker to force a user to restart the authentication process, preventing a legitimate user from establishing remote access VPN sessions.
Which versions are affected by CVE-2024-20331?
It affects 2 products.
Products include Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.
How do I fix CVE-2024-20331?
No fix has been published for CVE-2024-20331 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-2024-20331 being exploited?
There is no known exploitation of CVE-2024-20331 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-jrcg-6c8x-ff3h.