CVE-2023-20081 Denial of service in Cisco IOS
Remote attackers can cause device reloads via crafted DHCPv6 messages if they control the server or perform man-in-the-middle attacks.
- 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-2023-20081?
CVE-2023-20081 is a medium-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, published on 23 Mar 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the IPv6 DHCP (DHCPv6) client module of Cisco Adaptive Security Appliance (ASA) Software, Cisco Firepower Threat Defense (FTD) Software, Cisco IOS Software, and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient validation of DHCPv6 messages. An attacker could exploit this vulnerability by sending crafted DHCPv6 messages to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: To successfully exploit this vulnerability, the attacker would need to either control the DHCPv6 server or be in a man-in-the-middle position.
Which versions are affected by CVE-2023-20081?
It affects 4 products.
Products include Cisco Adaptive Security Appliance Software, Cisco Ios, Cisco Ios Xe, Cisco Secure Firewall Threat Defense.
How do I fix CVE-2023-20081?
No fix has been published for CVE-2023-20081 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-2023-20081 being exploited?
There is no known exploitation of CVE-2023-20081 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-h5mj-448h-fhr2.