← All Advisories

CVE-2026-20349: Cisco Secure Firewall

Status: KEV  |  Advisory ID: CVE-2026-20349

Key Details

CVECVE-2026-20349
CVSSCVSS 8.6 (High): attack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is changed; confidentiality impact is none; integrity impact is none; availability impact is high. (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H)
Affected productsCisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) , Cisco Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense
Exploitation statusListed in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating confirmed active exploitation.
Classified asCWE-244 (Improper Clearing of Heap Memory Before Release ('Heap Inspection'))
KEV listingAdded to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-08-11.
Federal remediation deadline2026-08-14 (CISA KEV, Binding Operational Directive).

What to Know

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 an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. 

This vulnerability is due to insufficient error checking when processing HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-20349