Actively exploited
Listed in CISA’s Known Exploited Vulnerabilities catalog since August 11, 2026.
CVE-2026-20349
Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) vulnerability
Added to KEV August 11, 2026
Alert details
- Source feed
- CISA KEV
- CVE ID
- CVE-2026-20349
- CWE
- CWE-244
- Affected products
- Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) · Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) · Cisco
What happened
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.
What it means for your business
Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2026-20349). 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. CISA remediation due date: 2026-08-14. If you need help checking exposure, call (864) 335-9223.
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.
CISA due date: August 14, 2026
Sources
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