{"id":"CVE-2021-40118","aliases":["EUVD-2021-27305","GHSA-6c9f-g24c-wm5r"],"status":"published","title":"Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Denial of Service Vulnerabilities","description":"A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.","severity":{"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":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.01362,"percentile":0.71993,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-121","CWE-20","CWE-787"],"published":"2021-10-27T18:56:54Z","modified":"2026-08-11T19:37:30Z","products":[{"vendor":"cisco","product":"adaptive_security_appliance"},{"vendor":"cisco","product":"adaptive_security_appliance_software"},{"vendor":"cisco","product":"asa_5505_firmware"},{"vendor":"cisco","product":"asa_5512-x_firmware"},{"vendor":"cisco","product":"asa_5515-x_firmware"},{"vendor":"cisco","product":"asa_5525-x_firmware"},{"vendor":"cisco","product":"asa_5545-x_firmware"},{"vendor":"cisco","product":"asa_5555-x_firmware"},{"vendor":"cisco","product":"asa_5580_firmware"},{"vendor":"cisco","product":"asa_5585-x_firmware"},{"vendor":"cisco","product":"cisco adaptive security appliance (asa) software"},{"vendor":"cisco","product":"secure_firewall_threat_defense"}],"references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asafdt-webvpn-dos-KSqJAKPA","tags":["vendor-advisory","x_refsource_CISCO","x_transferred","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-40118"},{"url":"https://github.com/advisories/GHSA-6c9f-g24c-wm5r"}],"sources":{"cve":[{"id":"CVE-2021-40118","title":"Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Denial of Service Vulnerabilities","description":"A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.","status":"published","published":"2021-10-27T18:56:54.065Z","modified":"2024-11-07T21:45:17.254Z","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":"cna"}],"cwes":["CWE-121"],"updated_at":"2026-11-02T14:33:01.852999Z"}],"euvd":[{"id":"EUVD-2021-27305","description":"A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.","status":"published","published":"2021-10-27T18:56:54Z","modified":"2024-11-07T21:45:17Z","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"}],"updated_at":"2026-11-03T00:05:07.826667Z"}],"ghsa":[{"id":"GHSA-6c9f-g24c-wm5r","title":"Multiple vulnerabilities in the web services interface of Cisco Adaptive Security Appliance (ASA)...","description":"Multiple vulnerabilities in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. These vulnerabilities are due to improper input validation when parsing HTTPS requests. An attacker could exploit these vulnerabilities by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.","status":"published","published":"2022-05-24T19:18:53Z","modified":"2023-08-25T05:02:41Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-20","CWE-121","CWE-787"],"updated_at":"2026-11-02T14:54:45.82233Z"}],"nvd":[{"id":"CVE-2021-40118","description":"A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.","status":"published","published":"2021-10-27T19:15:08.823Z","modified":"2026-08-11T19:37:30.88Z","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":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":7.1,"vector":"AV:N/AC:M/Au:N/C:N/I:N/A:C","level":"high","assessor":"primary"}],"cwes":["CWE-121","CWE-787"],"updated_at":"2026-11-02T14:07:00.549994Z"}]}}