CISA Adds Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Vulnerability CVE-2026-20349 to Known Exploited Vulnerabilities Catalog

CISA KEV Listing Record

CISA added CVE-2026-20349 (Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD)) to the Known Exploited Vulnerabilities () catalog on 2026-08-11 ^[2].

Original Technical Description

Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) contain a heap inspection vulnerability that could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. ^[2]

Official Required Action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. ^[2]

Individual Vulnerability Record

The U.S. National Vulnerability Database (NVD) provides an independent vulnerability record and description for CVE-2026-20349 ^[1].