--- id: "CVE-2024-20353" kind: "vulnerability" aliases: ["CVE-2024-20353"] title: "cisco adaptive security appliance software: A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco\u2026" severity: "high" cvss: 8.6 epss: null exploited: true status: "open" category: "infrastructure" products: [{"name": "Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.1", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.1.5", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.1.7", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.8", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.14", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.15", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.17", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.20", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.24", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.26", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.28", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.33", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.35", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.2.38", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3.8", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3.11", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3.14", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3.16", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3.18", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3.21", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3.26", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.3.29", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.3", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.7", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.8", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.10", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.12", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.15", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.17", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.20", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.22", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.25", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.26", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.29", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.32", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.33", "ecosystem": "vendor"}, {"name": "cisco adaptive security appliance software", "fixed": [], "affected": "= 9.8.4.34", "ecosystem": "vendor"}] ecosystems: ["vendor"] tags: ["cisco-asa", "cisco-ftd", "exploited", "firewall", "infrastructure"] not_affected_if: ["unknown"] published_at: "2024-04-24T00:00:00+00:00" first_seen_at: "2026-10-23T19:11:51+00:00" updated_at: "2026-10-23T22:29:05+00:00" sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2024-20353", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-20353", "first_seen_at": "2026-10-23T22:29:05+00:00"}] --- # cisco adaptive security appliance software: A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco… Cisco ASA and Firepower Threat Defense firewalls contain an infinite loop bug that an attacker can trigger remotely. Triggering it causes a denial of service, taking the device offline. _Summary, check and fix written by a model from the sources; labelled as such._ ## Affected - vendor:Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) affected ? fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.1 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.1.5 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.1.7 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.8 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.14 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.15 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.17 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.20 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.24 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.26 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.28 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.33 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.35 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.2.38 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3.8 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3.11 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3.14 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3.16 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3.18 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3.21 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3.26 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.3.29 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.3 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.7 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.8 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.10 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.12 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.15 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.17 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.20 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.22 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.25 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.26 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.29 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.32 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.33 fixed ? - vendor:cisco adaptive security appliance software affected = 9.8.4.34 fixed ? ## Fix Apply the mitigations in the Cisco advisory; CISA says to discontinue use of the product if mitigations are unavailable. Specific fixed versions: unknown ## Timeline - 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2024-20353 - 2026-10-23T22:29:05+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2024-20353 ## From the sources A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to incomplete error checking when parsing an HTTP header. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted web server on a device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads. --- _Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_