CVE-2020-17049

Name: CVE-2020-17049
Creator: NVD / NIST
Published: 2020-11-11T07:15:16.543+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.6/10EPSS 13.79%

Last modified Jun 17, 2026

CVE-2020-17049 is a medium-severity vulnerability rated 6.6/10 on the CVSS scale. 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). To 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. The update addresses this vulnerability by changing how the KDC validates service tickets used with KCD.. EPSS estimates a 13.79% chance of exploitation in the next 30 days.

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). To 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. The update addresses this vulnerability by changing how the KDC validates service tickets used with KCD.

Metrics

CVSS 3.1

6.6/10

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

13.79%

96.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-863

Affected Software

Vendor	Product	Versions
Microsoft	Windows Server 2012	All versions
Microsoft	Windows Server 2012	r2
Microsoft	Windows Server 2016	All versions
Microsoft	Windows Server 2016	20h2
Microsoft	Windows Server 2016	1903
Microsoft	Windows Server 2016	1909
Microsoft	Windows Server 2016	2004
Microsoft	Windows Server 2019	All versions
Samba	Samba	>= 4.1.0, < 4.13.13
Samba	Samba	>= 4.14.0, < 4.14.9
Samba	Samba	>= 4.15.0, < 4.15.1

References

http://www.openwall.com/lists/oss-security/2021/11/10/3Mailing List, Third Party Advisory
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-17049Patch, Vendor Advisory
https://security.gentoo.org/glsa/202309-06
http://www.openwall.com/lists/oss-security/2021/11/10/3Mailing List, Third Party Advisory
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-17049Patch, Vendor Advisory
https://security.gentoo.org/glsa/202309-06

Timeline

Published: Nov 11, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-17049?

How severe is CVE-2020-17049?

CVE-2020-17049 has a CVSS score of 6.6/10 (MEDIUM severity). The EPSS model estimates a 13.79% probability of exploitation in the next 30 days.

How do I fix CVE-2020-17049?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-17049?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST