--- id: CVE-2026-20331 title: >- As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense Software and Cisco Secure Firewall Management Center Software en… summary: >- As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense Software and Cisco Secure Firewall Management Center Software en… severity: critical cvss: 9.6 cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L' cwe: - CWE-693 vendor: Cisco product: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software affected: - secure_firewall_adaptive_security_appliance_asa_software 9.16.1 - secure_firewall_adaptive_security_appliance_asa_software 9.16.1.28 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.3 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.7 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.11 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.13 - secure_firewall_adaptive_security_appliance_asa_software 9.16.2.14 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.3 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.14 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.15 - secure_firewall_adaptive_security_appliance_asa_software 9.18.1.3 - secure_firewall_adaptive_security_appliance_asa_software 9.18.2 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.19 - secure_firewall_adaptive_security_appliance_asa_software 9.16.3.23 - secure_firewall_adaptive_security_appliance_asa_software 9.18.2.5 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4 - secure_firewall_adaptive_security_appliance_asa_software 9.18.2.7 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.9 - secure_firewall_adaptive_security_appliance_asa_software 9.18.2.8 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.14 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.18 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.39 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.19 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.46 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.27 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.53 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.55 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.38 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.39 - secure_firewall_adaptive_security_appliance_asa_software 9.18.3.56 - secure_firewall_adaptive_security_appliance_asa_software 9.20.1 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.42 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4 - secure_firewall_adaptive_security_appliance_asa_software 9.20.1.5 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4.5 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.48 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4.8 - secure_firewall_adaptive_security_appliance_asa_software 9.20.2 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.55 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4.22 - secure_firewall_adaptive_security_appliance_asa_software 9.20.2.10 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.57 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4.24 - secure_firewall_adaptive_security_appliance_asa_software 9.20.2.21 - secure_firewall_adaptive_security_appliance_asa_software 9.16.4.61 - secure_firewall_adaptive_security_appliance_asa_software 9.18.4.29 - secure_firewall_adaptive_security_appliance_asa_software 9.20.2.22 published: '2026-09-16' updated: '2026-09-18' sourceUpdated: '2026-09-18T20:17:14.087' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-20331' references: - url: >- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-asaftdfmc-uvpPROhN label: psirt@cisco.com - url: 'https://software.cisco.com' tags: - nvd - cve.org - csaf - vendor-advisory - cisco epss: 0.00229 epssPercentile: 0.13981 ssvc: exploitation: none automatable: 'no' technicalImpact: total timestamp: '2026-09-16T17:33:41.785706Z' ingestedAt: '2026-09-16T16:37:52.191Z' --- ## Overview As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense Software and Cisco Secure Firewall Management Center Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-20331 are related to the failure of protection mechanisms issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-693. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **cisco-sa-hardening-asaftdfmc-uvpPROhN** · Cisco · affected: Cisco Secure Firewall Management Center (FMC) (196 versions), Cisco Secure Firewall Adaptive Security Appliance (ASA) Software (893 versions), Cisco Secure Firewall Threat Defense (FTD) Software (171 versions) · updated 2026-09-18 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-asaftdfmc-uvpPROhN)