CVE-2026-20349KEV · OVERDUECWE-244

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

High · published August 11, 2026

Patch now

Confirmed exploited, and the score agrees

CVSS calls it high at 8.6. It is confirmed in active exploitation. It sits in the 81.4th percentile for exploit probability.

24
days past CISA
deadline
CVSS v3.1
8.6
EPSS
2%
Percentile
81.4
In the wild
Confirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.6 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.02213 · 81.4th percentile
Weakness
CWE-244 · Improper Clearing of Heap Memory Before Release ('Heap Inspection')
Published
2026-08-11T21:17Z
KEV added
2026-08-11 · due 2026-08-14
Affected products (197)
ProductVersionsFixed in
cisco/adaptive_security_appliance_softwareall versions
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References (2)
EPSS history
Timeline
  • 11 AUG 17:06Z
    Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability
    cvelistv5