{"id":"CVE-2026-20323","title":"A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer device and obtain access at the leve…","summary":"A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer device and obtain access at the leve…","severity":"high","cvss":8.3,"cvssVector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","cwe":["CWE-295"],"vendor":"Cisco","product":"Cisco Secure Firewall Management Center (FMC)","affected":["secure_firewall_management_center_fmc 7.0.0","secure_firewall_management_center_fmc 7.0.0.1","secure_firewall_management_center_fmc 7.0.1","secure_firewall_management_center_fmc 7.0.1.1","secure_firewall_management_center_fmc 7.0.2","secure_firewall_management_center_fmc 7.2.0","secure_firewall_management_center_fmc 7.0.2.1","secure_firewall_management_center_fmc 7.0.3","secure_firewall_management_center_fmc 7.2.0.1","secure_firewall_management_center_fmc 7.0.4","secure_firewall_management_center_fmc 7.2.1","secure_firewall_management_center_fmc 7.0.5","secure_firewall_management_center_fmc 7.3.0","secure_firewall_management_center_fmc 7.2.2","secure_firewall_management_center_fmc 7.3.1","secure_firewall_management_center_fmc 7.2.3","secure_firewall_management_center_fmc 7.2.3.1","secure_firewall_management_center_fmc 7.2.4","secure_firewall_management_center_fmc 7.0.6","secure_firewall_management_center_fmc 7.2.4.1","secure_firewall_management_center_fmc 7.2.5","secure_firewall_management_center_fmc 7.3.1.1","secure_firewall_management_center_fmc 7.4.0","secure_firewall_management_center_fmc 7.0.6.1","secure_firewall_management_center_fmc 7.2.5.1","secure_firewall_management_center_fmc 7.4.1","secure_firewall_management_center_fmc 7.2.6","secure_firewall_management_center_fmc 7.4.1.1","secure_firewall_management_center_fmc 7.0.6.2","secure_firewall_management_center_fmc 7.2.7","secure_firewall_management_center_fmc 7.2.5.2","secure_firewall_management_center_fmc 7.3.1.2","secure_firewall_management_center_fmc 7.2.8","secure_firewall_management_center_fmc 7.6.0","secure_firewall_management_center_fmc 7.4.2","secure_firewall_management_center_fmc 7.2.8.1","secure_firewall_management_center_fmc 7.0.6.3","secure_firewall_management_center_fmc 7.4.2.1","secure_firewall_management_center_fmc 7.2.9","secure_firewall_management_center_fmc 7.0.7","secure_firewall_management_center_fmc 7.7.0","secure_firewall_management_center_fmc 7.4.2.2","secure_firewall_management_center_fmc 7.2.10","secure_firewall_management_center_fmc 7.6.1","secure_firewall_management_center_fmc 7.4.2.3","secure_firewall_management_center_fmc 7.0.8","secure_firewall_management_center_fmc 7.6.2","secure_firewall_management_center_fmc 7.7.10","secure_firewall_management_center_fmc 7.2.10.1","secure_firewall_management_center_fmc 7.0.8.1"],"published":"2026-09-16","updated":"2026-09-18","sourceUpdated":"2026-09-18T13:28:28.567","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-20323","references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmcftd-sftun-multivulns-WGVHOrN3","label":"psirt@cisco.com"},{"url":"https://software.cisco.com"}],"tags":["nvd","cve.org","csaf","vendor-advisory","cisco"],"epss":0.00089,"epssPercentile":0.00475,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-17T03:57:39.569102Z"},"ingestedAt":"2026-09-16T16:37:52.185Z","slug":"CVE-2026-20323","body":"## Overview\n\nA vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer device and obtain access at the level of the manager role, which is equivalent to root.\r\n\r\nThis vulnerability is due to improper management of the TLS certificate for the sftunnel management connection. An attacker could exploit this vulnerability by connecting to the sftunnel port using a crafted TLS certificate. A successful exploit could allow the attacker to become a registered sftunnel peer with root access.\r\nNote: The attack is successful only if the sftunnel connection is down or the attack can disrupt the sftunnel connection long enough to execute the attack.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **cisco-sa-fmcftd-sftun-multivulns-WGVHOrN3** · Cisco · affected: Cisco Secure Firewall Management Center (FMC) Appliances, Cisco Firepower 2100 Series, Cisco Firepower 1000 Series, Cisco ASA 5500-X Series Firewalls, Cisco 3000 Series Industrial Security Appliances (ISA), Cisco Firepower 9000 Series, … · updated 2026-09-16 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmcftd-sftun-multivulns-WGVHOrN3)","depth":"twilight","depthScore":46,"depthScoreParts":{"impact":45.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}