{"id":"CVE-2021-1402","aliases":["EUVD-2021-6869","GHSA-pmvv-gfvh-28f5"],"status":"published","title":"Cisco Firepower Threat Defense Software SSL Decryption Policy Denial of Service Vulnerability","description":"A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message through an affected device. SSL/TLS messages sent to an affected device do not trigger this vulnerability. A successful exploit could allow the attacker to cause a process to crash. This crash would then trigger a reload of the device. No manual intervention is needed to recover the device after the reload.","severity":{"version":"3.0","score":8.6,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.01397,"percentile":0.72627,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-119","CWE-20"],"published":"2021-04-29T17:15:17Z","modified":"2026-08-11T19:33:44Z","products":[{"vendor":"cisco","product":"cisco firepower threat defense software"},{"vendor":"cisco","product":"secure_firewall_threat_defense"}],"references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-ssl-decrypt-dos-DdyLuK6c","tags":["vendor-advisory","x_refsource_CISCO","x_transferred","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-1402"},{"url":"https://github.com/advisories/GHSA-pmvv-gfvh-28f5"}],"sources":{"cve":[{"id":"CVE-2021-1402","title":"Cisco Firepower Threat Defense Software SSL Decryption Policy Denial of Service Vulnerability","description":"A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message through an affected device. SSL/TLS messages sent to an affected device do not trigger this vulnerability. A successful exploit could allow the attacker to cause a process to crash. This crash would then trigger a reload of the device. No manual intervention is needed to recover the device after the reload.","status":"published","published":"2021-04-29T17:15:17.61Z","modified":"2024-11-08T23:25:17.062Z","cvss":[{"version":"3.0","score":8.6,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-119"],"updated_at":"2026-11-02T14:33:08.409321Z"}],"euvd":[{"id":"EUVD-2021-6869","description":"A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message through an affected device. SSL/TLS messages sent to an affected device do not trigger this vulnerability. A successful exploit could allow the attacker to cause a process to crash. This crash would then trigger a reload of the device. No manual intervention is needed to recover the device after the reload.","status":"published","published":"2021-04-29T17:15:17Z","modified":"2024-11-08T23:25:17Z","cvss":[{"version":"3.0","score":8.6,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-03T00:05:05.926487Z"}],"ghsa":[{"id":"GHSA-pmvv-gfvh-28f5","title":"A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense ...","description":"A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message through an affected device. SSL/TLS messages sent to an affected device do not trigger this vulnerability. A successful exploit could allow the attacker to cause a process to crash. This crash would then trigger a reload of the device. No manual intervention is needed to recover the device after the reload.","status":"published","published":"2022-05-24T17:49:12Z","modified":"2023-01-27T05:03:38Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-20","CWE-119"],"updated_at":"2026-11-02T14:42:17.140708Z"}],"nvd":[{"id":"CVE-2021-1402","description":"A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message through an affected device. SSL/TLS messages sent to an affected device do not trigger this vulnerability. A successful exploit could allow the attacker to cause a process to crash. This crash would then trigger a reload of the device. No manual intervention is needed to recover the device after the reload.","status":"published","published":"2021-04-29T18:15:08.923Z","modified":"2026-08-11T19:33:44.513Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"3.0","score":8.6,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","level":"high","assessor":"secondary"},{"version":"2.0","score":7.8,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:C","level":"high","assessor":"primary"}],"cwes":["CWE-119","CWE-20"],"updated_at":"2026-11-02T14:06:52.81233Z"}]}}