{"cve":"CVE-2026-20248","nvd":{"published":"2026-09-16T21:17:08.320","modified":"2026-09-18T13:28:28.567","status":"Awaiting Analysis","description":"A vulnerability in the DNS over TCP implementation of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the TCP DNS response handler to unexpectedly restart, causing the device to reload.\r\n\r\nThis vulnerability is due to a logic error when parsing a DNS query and tracking the size of the incoming buffers. An attacker could exploit this vulnerability by formatting a crafted reply to a DNS query sent from the targeted device. A successful exploit could allow the attacker to cause the device to reload, causing a denial of service (DoS) condition.\r\nNote: The attacker must be able to respond to DNS queries from the device, either by controlling the DNS service or through a machine-in-the-middle attack.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H","score":6.8},"cwes":["CWE-195"],"references":["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-tcpdns-dos-p6dUnjr5"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:54:41.405518556+00:00"},"epss":{"cve":"CVE-2026-20248","score":0.00455,"percentile":0.39474,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}