CVE-2020-17049 Kerberos KDC Security Feature Bypass Vulnerability
Attackers can bypass Kerberos Constrained Delegation restrictions by tampering with service tickets, requiring a compromised service configured for KCD.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-17049?
CVE-2020-17049 is a medium-severity vulnerability in Microsoft Windows Server 2012, published on 11 Nov 2020. An attacker needs administrator access to exploit it, with no action from the victim.
Official 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.
Weakness: CWE-863
Which versions are affected by CVE-2020-17049?
It affects 4 products.
Linux distribution packages (23)
krb5-devel AlmaLinux:9 | All versions | 1.20.1-8.el9 |
krb5-libs AlmaLinux:9 | All versions | 1.20.1-8.el9 |
krb5-pkinit AlmaLinux:9 | All versions | 1.20.1-8.el9 |
krb5-server AlmaLinux:9 | All versions | 1.20.1-8.el9 |
krb5-server-ldap AlmaLinux:9 | All versions | 1.20.1-8.el9 |
krb5-workstation AlmaLinux:9 | All versions | 1.20.1-8.el9 |
libkadm5 AlmaLinux:9 | All versions | 1.20.1-8.el9 |
krb5-devel Red Hat:enterprise_linux:9::appstream | All versions | 0:1.20.1-8.el9 |
krb5 Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-debugsource Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-libs Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-libs-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-pkinit Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-pkinit-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-server Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-server-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-server-ldap Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-server-ldap-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-workstation Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
krb5-workstation-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
libkadm5 Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
libkadm5-debuginfo Red Hat:enterprise_linux:9::baseos | All versions | 0:1.20.1-8.el9 |
Products include Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Samba Samba.
How do I fix CVE-2020-17049?
Apply the vendor's patch.
Is CVE-2020-17049 being exploited?
There is no known exploitation of CVE-2020-17049 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows Server 2012
- CVE-2025-59287 Microsoft Windows Server Update Service (WSUS) Deserialization of Untrusted Data
- CVE-2026-69595 Windows Services for NFS ONCRPC XDR Driver Remote Code Execution Vulnerability
- CVE-2026-78445 Windows Services for NFS ONCRPC XDR Driver Remote Code Execution Vulnerability
- CVE-2026-41089 Windows Netlogon Remote Code Execution Vulnerability
- CVE-2024-43639 Windows KDC Proxy Remote Code Execution Vulnerability
Sources
Also known as ALSA-2023:2570, AZL-10661, AZL-36992, GHSA-g2p3-j47p-8cwj, RHSA-2023:2570, openSUSE-SU-2024:13200-1.