🔐 CVE Alert

CVE-2026-20349

HIGH 8.6 ⚠️ CISA KEV

Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability

CVSS Score
8.6
EPSS Score
2.2%
EPSS Percentile
82th

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.

CWE CWE-244
Vendor cisco
Product cisco secure firewall adaptive security appliance (asa) software
Ecosystems
Industries
NetworkingTelecommunications
Published Aug 11, 2026
Last Updated Sep 16, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

Affected Versions

Cisco / Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
9.16.1 9.16.1.28 9.16.2 9.16.2.3 9.16.2.7 9.16.2.11 9.16.2.13 9.16.2.14 9.16.3.3 9.16.3 9.16.3.14 9.18.1 9.16.3.15 9.18.1.3 9.18.2 9.16.3.19 9.16.3.23 9.18.2.5 9.16.4 9.18.2.7 9.19.1 9.16.4.9 9.18.2.8 9.16.4.14 9.18.3 9.19.1.5 9.16.4.18 9.19.1.9 9.18.3.39 9.16.4.19 9.19.1.12 9.18.3.46 9.16.4.27 9.19.1.18 9.18.3.53 9.18.3.55 9.16.4.38 9.16.4.39 9.18.3.56 9.20.1 9.16.4.42 9.19.1.22 9.18.4 9.20.1.5 9.18.4.5 9.19.1.24 9.16.4.48 9.18.4.8 9.20.2 9.19.1.27 9.16.4.55 9.18.4.22 9.20.2.10 9.16.4.57 9.19.1.28 9.18.4.24 9.20.2.21 9.16.4.61 9.19.1.31 9.18.4.29 9.20.2.22 9.16.4.62 9.18.4.34 9.20.3 9.16.4.67 9.16.4.70 9.18.4.40 9.23.1 9.22.1.1 9.16.4.71 9.20.3.4 9.18.4.47 9.20.3.7 9.19.1.37 9.16.4.76 9.20.3.9 9.19.1.38 9.18.4.50 9.22.1.3 9.20.3.10 9.22.1.2 9.18.4.52 9.20.3.13 9.22.1.6 9.18.4.53 9.16.4.82 9.22.2 9.20.3.16 9.19.1.42 9.18.4.57 9.16.4.84 9.23.1.3 9.20.3.20 9.22.2.4 9.23.1.7 9.20.4 9.22.2.9 9.23.1.13 9.20.4.7 9.22.2.13 9.18.4.66 9.20.4.10 9.23.1.19 9.16.4.85 9.22.2.14 9.18.4.67 9.24.1 9.18.4.68 9.23.1.22 9.20.4.14 9.22.2.20 9.18.4.71 9.20.4.19 9.23.1.26 9.16.4.89 9.22.2.32 9.18.4.76 9.22.3 9.24.1.5 9.20.4.22 9.24.1.9 9.20.4.28 9.22.3.5 9.16.4.92 9.18.4.135 9.23.1.195 9.20.4.30 9.24.1.155 9.23.1.32 9.24.1.11 9.20.4.34 9.18.4.82
Cisco / Cisco Secure Firewall Threat Defense (FTD) Software
7.0.0 7.0.0.1 7.0.1 7.0.1.1 7.0.2 7.2.0 7.0.2.1 7.0.3 7.2.0.1 7.0.4 7.2.1 7.0.5 7.3.0 7.2.2 7.2.3 7.3.1 7.2.4 7.0.6 7.2.5 7.2.4.1 7.3.1.1 7.4.0 7.0.6.1 7.2.5.1 7.4.1 7.2.6 7.0.6.2 7.4.1.1 7.2.7 7.2.5.2 7.3.1.2 7.2.8 7.6.0 7.4.2 7.2.8.1 7.0.6.3 7.4.2.1 7.2.9 7.0.7 7.7.0 7.4.2.2 7.2.10 7.6.1 7.4.2.3 7.0.8 7.6.2 7.7.10 7.7.11 7.0.8.1 7.6.2.1 7.7.10.1 7.4.2.4 7.2.10.2 7.4.3 7.6.4 10.0.0 7.4.4 7.0.9 7.2.11 7.4.7 10.0.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗
sec.cloudapps.cisco.com: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-dos-dzv4mQFF cisa.gov: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20349