{"schemaVersion":3,"id":"CVE-2021-1402","aliases":[],"status":"published","duplicateOf":null,"title":null,"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.","dates":{"published":"2021-04-29T17:15:17.610Z","modified":"2024-11-08T23:25:17.062Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":8.6,"severity":"high","version":"3.0","versionLabel":"v3.0","source":"CVE.org","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.0","versionLabel":"v3.0","source":"CVE.org","score":8.6,"severity":"high","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":8.6,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.0","versionLabel":"v3.0","source":"NVD","score":8.6,"severity":"high","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false},{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":7.8,"severity":"high","vector":"AV:N/AC:L/Au:N/C:N/I:N/A:C","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.01397,"percentile":0.71978,"severity":"low","asOf":"2026-10-18T00:00:00.000Z","change":{"pp":0.010999999999999899,"baselineDate":"2026-09-18T00:00:00.000Z","baselineScore":0.01386},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.01397,"percentile":0.71978}],"last30":[{"date":"2026-09-18T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.01386,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.01397,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.01397,"percentile":0.71978}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-119","name":"Improper Restriction of Operations within the Bounds of a Memory Buffer","description":"The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.","type":"weakness","status":"Stable","abstraction":"Class","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/119.html"},{"id":"CWE-20","name":"Improper Input Validation","description":"The product receives input or data, but it does\n        not validate or incorrectly validates that the input has the\n        properties that are required to process the data safely and\n        correctly.","type":"weakness","status":"Stable","abstraction":"Class","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/20.html"}],"affected":[{"vendor":"cisco","product":"cisco firepower threat defense software","name":"Cisco Firepower Threat Defense Software","label":"cisco firepower threat defense software","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"n/a","noFixRecorded":false,"fixedIn":null}],"versionsText":"n/a","eol":null,"hubHref":"/vendor/cisco/cisco_firepower_threat_defense_software"},{"vendor":"cisco","product":"secure_firewall_threat_defense","name":"secure firewall threat defense","label":"secure_firewall_threat_defense","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 6.3.0, < 6.4.0","noFixRecorded":false,"fixedIn":null},{"text":"≥ 6.5.0, < 6.6.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 6.3.0, < 6.4.0 | ≥ 6.5.0, < 6.6.0","eol":null,"hubHref":"/vendor/cisco/secure_firewall_threat_defense"}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-ssl-decrypt-dos-DdyLuK6c","label":"tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-ssl-decrypt-dos-DdyLuK6c","hostname":"tools.cisco.com","tags":["Vendor Advisory","X Refsource CISCO"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2021-04-29T17:15:17.610Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2024-11-08T23:25:17.062Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":35,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-19T06:20:04.587Z","stale":false,"partial":false}}