CVE-2026-20349
Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability
Exploited in the wild
This vulnerability is on the CISA Known Exploited Vulnerabilities list, added 2026-08-11. Federal due date: 2026-08-14.
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.
Impact
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.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Cisco | Cisco Secure Firewall Adaptive Security Appliance (ASA) Software | Versions 9.22.2.9, 9.20.4.28, 9.18.4.52, 9.24.1.11, 9.16.2.3, 9.16.2.13 |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | Versions 7.2.4.1, 7.0.5, 7.7.11, 7.4.0, 7.4.1.1, 7.2.9 |
| Cisco | Adaptive Security Appliance Software | Versions 9.16.1, 9.16.1.28, 9.16.2, 9.16.2.3, 9.16.2.7, 9.16.2.11 |
| Cisco | Secure Firewall Threat Defense | Versions 7.0.0, 7.0.0.1, 7.0.1, 7.0.1.1, 7.0.2, 7.0.2.1 |