Vulnerability Description
A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to ineffective memory management of the VPN web server. An attacker could exploit this vulnerability by sending a large number of crafted HTTP requests to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Adaptive Security Appliance Software | >= 9.12.1, < 9.16.4.84 |
| Cisco | Firepower Threat Defense Software | >= 6.4.0, < 7.0.9 |
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-20039?
CVE-2026-20039 is a vulnerability with a CVSS score of 8.6 (HIGH). A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote...
How severe is CVE-2026-20039?
CVE-2026-20039 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-20039?
Check the references section above for vendor advisories and patch information. Affected products include: Cisco Adaptive Security Appliance Software, Cisco Firepower Threat Defense Software.