CVE-2026-20349Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability
Updated under an hour ago ()
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It affects Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and 3 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Aug 11, 2026; federal agencies had to remediate by Aug 14, 2026. Treat that date as your deadline.
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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
- 8.6 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- Weakness (CWE)
- CWE-244
- Known exploited
- Added to CISA KEV Aug 11, 2026; federal remediation due Aug 14, 2026Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- EPSS (exploitation in the next 30 days)
- 1.01% (percentile 62)
- Assigned by
- cisco
- NVD analysis
- Analyzed
- Record last updated
- Sep 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software cisco:secure_firewall_adaptive_security_appliance_asa_software (from the name) | 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; and 124 more ranges | CNA record |
Cisco Cisco Secure Firewall Threat Defense (FTD) Software cisco:secure_firewall_threat_defense_ftd_software (from the name) | 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; and 53 more ranges | CNA record |
cisco adaptive_security_appliance_software cisco:adaptive_security_appliance_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; and 125 more ranges | NVD |
cisco secure_firewall_threat_defense cisco:secure_firewall_threat_defense | 7.0.0; 7.0.0.1; 7.0.1; 7.0.1.1; 7.0.2; 7.0.2.1; 7.0.3; 7.0.4; and 56 more ranges | NVD |
References
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-dos-dzv4mQFFvendor-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20349us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.