{"id":"CVE-2020-17049","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-17049","generatedAt":"2026-10-27T21:16:21.206Z","title":"A security feature bypass vulnerability exists in the way Key Distribution Center (KDC) determines if a service ticket can be used for delegation via Kerberos Constrained Delegation (KCD).","description":"A security feature bypass vulnerability exists in the way Key Distribution Center (KDC) determines if a service ticket can be used for delegation via Kerberos Constrained Delegation (KCD).\nTo exploit the vulnerability, a compromised service that is configured to use KCD could tamper with a service ticket that is not valid for delegation to force the KDC to accept it.\nThe update addresses this vulnerability by changing how the KDC validates service tickets used with KCD.","published":"2020-11-11T07:15:17.000Z","lastModified":"2026-06-17T02:58:35.000Z","status":"Modified","sourceIdentifier":"secure@microsoft.com","cvss":{"version":"3.1","score":6.6,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-863"],"affected":["microsoft/windows server 2012","microsoft/windows server 2016","microsoft/windows server 2019","samba/samba"],"epss":{"score":0.13794,"percentile":0.96492,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 13.8%, higher than 96% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://www.openwall.com/lists/oss-security/2021/11/10/3","tags":["Mailing List","Third Party Advisory"],"source":"secure@microsoft.com"},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-17049","tags":["Patch","Vendor Advisory"],"source":"secure@microsoft.com"},{"url":"https://security.gentoo.org/glsa/202309-06","source":"secure@microsoft.com"},{"url":"http://www.openwall.com/lists/oss-security/2021/11/10/3","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-17049","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202309-06","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-17049","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}