CVE-2026-20349CiscoFirewall and VPNAugust 11, 2026

Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Vulnerability

High 8.6Actively exploited

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.

What to do

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.

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Details

Vendor
Cisco
Product
Cisco Secure Firewall ASA e FTD
CVE
CVE-2026-20349
Affected versions
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.16: 37 versions, from 9.16.1 to 9.16.4.92
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.18: 32 versions, from 9.18.1 to 9.18.4.135
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.19: 13 versions, from 9.19.1 to 9.19.1.42
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.20: 23 versions, from 9.20.1 to 9.20.4.34
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.23: 9 versions, from 9.23.1 to 9.23.1.195
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.22: 13 versions, from 9.22.1.1 to 9.22.3.5
Cisco Secure Firewall Adaptive Security Appliance (ASA) Soft 9.24: 5 versions, from 9.24.1 to 9.24.1.155
Cisco Secure Firewall Threat Defense (FTD) Software 7.0: 17 versions, from 7.0.0 to 7.0.9
Cisco Secure Firewall Threat Defense (FTD) Software 7.2: 18 versions, from 7.2.0 to 7.2.11
Cisco Secure Firewall Threat Defense (FTD) Software 7.3: 4 versions, from 7.3.0 to 7.3.1.2
Cisco Secure Firewall Threat Defense (FTD) Software 7.4: 11 versions, from 7.4.0 to 7.4.7
Cisco Secure Firewall Threat Defense (FTD) Software 7.6: 5 versions, from 7.6.0 to 7.6.4
Cisco Secure Firewall Threat Defense (FTD) Software 7.7: 4 versions, from 7.7.0 to 7.7.11
Cisco Secure Firewall Threat Defense (FTD) Software 10.0: 10.0.0; 10.0.2 (from the advisory and NVD; check the exact builds in the official advisory)
CVSS score
8.6
Actively exploited
Yes, listed in the CISA Known Exploited Vulnerabilities catalog
CISA due date
August 14, 2026 (deadline for US federal agencies: a good benchmark for you too)
Source
CISA KEV – original advisory
Published
August 11, 2026

The description and the recommended action are quoted from the public advisory; severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.

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