CVE-2026-20349: cisco adaptive_security_appliance_software, cisco secure_firewall_threat_defense

CVSS 8.6 (high) · listed as exploited by CISA since 2026-08-11 · published 2026-08-11

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.

Affected products (NVD): cisco adaptive_security_appliance_software, cisco secure_firewall_threat_defense

Weakness: CWE-244

Source: NVD CVE-2026-20349

References

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

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