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CVE-2026-20349

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

8.6 HIGHActively exploited (CISA KEV)EPSS 1.01%
  1. Published11 Aug 2026
  2. Added to CISA KEV11 Aug 2026
  3. Remediation due14 Aug 2026
Actively exploited (CISA KEV)

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.

Added to KEV: 11 Aug 2026Federal remediation due: 14 Aug 2026

Description

A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.  This vulnerability is due to insufficient error checking when processing HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the Remote Access SSL VPN service on an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeChanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected products

Cisco Secure Firewall Threat Defense10.0.0 · 10.0.2 · 7.0.0 · 7.0.0.1
Cisco Adaptive Security Appliance Software9.16.1 · 9.16.1.28 · 9.16.2 · 9.16.2.11

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-200398.6
A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security…

Frequently asked

Is CVE-2026-20349 being actively exploited?

Yes. CVE-2026-20349 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 11 Aug 2026.

How severe is CVE-2026-20349?

CVE-2026-20349 has a CVSS 3.1 base score of 8.6, rated high. EPSS estimates a 1.01% probability of exploitation.

Which products are affected by CVE-2026-20349?

Affected products include Cisco Secure Firewall Threat Defense, Cisco Adaptive Security Appliance Software.

How do I fix CVE-2026-20349?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-20349 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.