Live › vulnerability › CVE-2026-20349
Go to dashboardA heap inspection flaw in Cisco ASA and Secure Firewall Threat Defense lets an unauthenticated remote attacker force the device to reload unexpectedly. The result is a denial of service on the firewall, and CISA lists it as known exploited.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 19:11 UTC, 5h before NVD. All times on this page are UTC.
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.
| Product | Ecosystem | Affected | Fixed in |
|---|---|---|---|
| Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) | vendor | – | – |
| cisco adaptive security appliance software | vendor | = 9.16.1 | – |
| cisco adaptive security appliance software | vendor | = 9.16.1.28 | – |
| cisco adaptive security appliance software | vendor |
| = 9.16.2 |
| – |
| cisco adaptive security appliance software | vendor | = 9.16.2.3 | – |
| cisco adaptive security appliance software | vendor | = 9.16.2.7 | – |
| cisco adaptive security appliance software | vendor | = 9.16.2.11 | – |
| cisco adaptive security appliance software | vendor | = 9.16.2.13 | – |
| cisco adaptive security appliance software | vendor | = 9.16.2.14 | – |
| cisco adaptive security appliance software | vendor | = 9.16.3 | – |
| cisco adaptive security appliance software | vendor | = 9.16.3.3 | – |
| cisco adaptive security appliance software | vendor | = 9.16.3.14 | – |
| cisco adaptive security appliance software | vendor | = 9.16.3.15 | – |
| cisco adaptive security appliance software | vendor | = 9.16.3.19 | – |
| cisco adaptive security appliance software | vendor | = 9.16.3.23 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.9 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.14 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.19 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.27 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.38 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.39 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.42 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.48 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.55 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.57 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.61 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.62 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.67 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.70 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.71 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.76 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.82 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.84 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.85 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.89 | – |
| cisco adaptive security appliance software | vendor | = 9.16.4.92 | – |
| cisco adaptive security appliance software | vendor | = 9.18.1 | – |
| cisco adaptive security appliance software | vendor | = 9.18.1.3 | – |
| cisco adaptive security appliance software | vendor | = 9.18.2 | – |
| cisco adaptive security appliance software | vendor | = 9.18.2.5 | – |
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
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 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.
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