CVE-2025-20244 Denial of service in Cisco Adaptive Security Appliance (ASA) Software
Authenticated remote attackers can cause Cisco ASA and FTD devices to reload via crafted HTTP requests to the SSL VPN service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-20244?
CVE-2025-20244 is a high-severity denial of service vulnerability in Cisco Adaptive Security Appliance (ASA) Software, published on 14 Aug 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow a remote attacker that is authenticated as a VPN user 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 field value. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause a DoS condition, which would cause the affected device to reload.
Weakness: CWE-1287
Which versions are affected by CVE-2025-20244?
How do I fix CVE-2025-20244?
No fix has been published for CVE-2025-20244 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-2025-20244 being exploited?
There is no known exploitation of CVE-2025-20244 in the wild and no public exploit code.
Sources
Also known as GHSA-jj2c-3m89-73r8.