Vulnerability Intelligence Report
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability
CVE-2026-20349
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.
CISA KEV
SSVC: Active Exploitation
Automatable
CVSS Base Score
8.6
HIGH
Exploitability:3.9
Impact Score:4.0
EPSS Probability:2.21%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-244 ↗Improper Clearing of Heap Memory Before Release ('Heap Inspection')
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Cisco | Cisco Secure Firewall Adaptive Security Appliance (ASA) Software | 9.16.1 (affected), 9.16.1.28 (affected), 9.16.2 (affected), 9.16.2.3 (affected), 9.16.2.7 (affected), 9.16.2.11 (affected), 9.16.2.13 (affected), 9.16.2.14 (affected), 9.16.3.3 (affected), 9.16.3 (affected), 9.16.3.14 (affected), 9.18.1 (affected), 9.16.3.15 (affected), 9.18.1.3 (affected), 9.18.2 (affected), 9.16.3.19 (affected), 9.16.3.23 (affected), 9.18.2.5 (affected), 9.16.4 (affected), 9.18.2.7 (affected), 9.19.1 (affected), 9.16.4.9 (affected), 9.18.2.8 (affected), 9.16.4.14 (affected), 9.18.3 (affected), 9.19.1.5 (affected), 9.16.4.18 (affected), 9.19.1.9 (affected), 9.18.3.39 (affected), 9.16.4.19 (affected), 9.19.1.12 (affected), 9.18.3.46 (affected), 9.16.4.27 (affected), 9.19.1.18 (affected), 9.18.3.53 (affected), 9.18.3.55 (affected), 9.16.4.38 (affected), 9.16.4.39 (affected), 9.18.3.56 (affected), 9.20.1 (affected), 9.16.4.42 (affected), 9.19.1.22 (affected), 9.18.4 (affected), 9.20.1.5 (affected), 9.18.4.5 (affected), 9.19.1.24 (affected), 9.16.4.48 (affected), 9.18.4.8 (affected), 9.20.2 (affected), 9.19.1.27 (affected), 9.16.4.55 (affected), 9.18.4.22 (affected), 9.20.2.10 (affected), 9.16.4.57 (affected), 9.19.1.28 (affected), 9.18.4.24 (affected), 9.20.2.21 (affected), 9.16.4.61 (affected), 9.19.1.31 (affected), 9.18.4.29 (affected), 9.20.2.22 (affected), 9.16.4.62 (affected), 9.18.4.34 (affected), 9.20.3 (affected), 9.16.4.67 (affected), 9.16.4.70 (affected), 9.18.4.40 (affected), 9.23.1 (affected), 9.22.1.1 (affected), 9.16.4.71 (affected), 9.20.3.4 (affected), 9.18.4.47 (affected), 9.20.3.7 (affected), 9.19.1.37 (affected), 9.16.4.76 (affected), 9.20.3.9 (affected), 9.19.1.38 (affected), 9.18.4.50 (affected), 9.22.1.3 (affected), 9.20.3.10 (affected), 9.22.1.2 (affected), 9.18.4.52 (affected), 9.20.3.13 (affected), 9.22.1.6 (affected), 9.18.4.53 (affected), 9.16.4.82 (affected), 9.22.2 (affected), 9.20.3.16 (affected), 9.19.1.42 (affected), 9.18.4.57 (affected), 9.16.4.84 (affected), 9.23.1.3 (affected), 9.20.3.20 (affected), 9.22.2.4 (affected), 9.23.1.7 (affected), 9.20.4 (affected), 9.22.2.9 (affected), 9.23.1.13 (affected), 9.20.4.7 (affected), 9.22.2.13 (affected), 9.18.4.66 (affected), 9.20.4.10 (affected), 9.23.1.19 (affected), 9.16.4.85 (affected), 9.22.2.14 (affected), 9.18.4.67 (affected), 9.24.1 (affected), 9.18.4.68 (affected), 9.23.1.22 (affected), 9.20.4.14 (affected), 9.22.2.20 (affected), 9.18.4.71 (affected), 9.20.4.19 (affected), 9.23.1.26 (affected), 9.16.4.89 (affected), 9.22.2.32 (affected), 9.18.4.76 (affected), 9.22.3 (affected), 9.24.1.5 (affected), 9.20.4.22 (affected), 9.24.1.9 (affected), 9.20.4.28 (affected), 9.22.3.5 (affected), 9.16.4.92 (affected), 9.18.4.135 (affected), 9.23.1.195 (affected), 9.20.4.30 (affected), 9.24.1.155 (affected), 9.23.1.32 (affected), 9.24.1.11 (affected), 9.20.4.34 (affected), 9.18.4.82 (affected) |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 7.0.0 (affected), 7.0.0.1 (affected), 7.0.1 (affected), 7.0.1.1 (affected), 7.0.2 (affected), 7.2.0 (affected), 7.0.2.1 (affected), 7.0.3 (affected), 7.2.0.1 (affected), 7.0.4 (affected), 7.2.1 (affected), 7.0.5 (affected), 7.3.0 (affected), 7.2.2 (affected), 7.2.3 (affected), 7.3.1 (affected), 7.2.4 (affected), 7.0.6 (affected), 7.2.5 (affected), 7.2.4.1 (affected), 7.3.1.1 (affected), 7.4.0 (affected), 7.0.6.1 (affected), 7.2.5.1 (affected), 7.4.1 (affected), 7.2.6 (affected), 7.0.6.2 (affected), 7.4.1.1 (affected), 7.2.7 (affected), 7.2.5.2 (affected), 7.3.1.2 (affected), 7.2.8 (affected), 7.6.0 (affected), 7.4.2 (affected), 7.2.8.1 (affected), 7.0.6.3 (affected), 7.4.2.1 (affected), 7.2.9 (affected), 7.0.7 (affected), 7.7.0 (affected), 7.4.2.2 (affected), 7.2.10 (affected), 7.6.1 (affected), 7.4.2.3 (affected), 7.0.8 (affected), 7.6.2 (affected), 7.7.10 (affected), 7.7.11 (affected), 7.0.8.1 (affected), 7.6.2.1 (affected), 7.7.10.1 (affected), 7.4.2.4 (affected), 7.2.10.2 (affected), 7.4.3 (affected), 7.6.4 (affected), 10.0.0 (affected), 7.4.4 (affected), 7.0.9 (affected), 7.2.11 (affected), 7.4.7 (affected), 10.0.2 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Cisco Systems, Inc. · Hosted Service · USA |
| Reserved | 2025-10-08T11:59:15 |
| Published | 2026-08-11T17:06:03 |
| Last Updated | 2026-09-16T20:15:35 |
Community Chatter & Buzz