MSRC-CVE-2025-21218 — Windows Kerberos Denial of Service Vulnerability

Summary

Impact: Denial of Service. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

How could an attacker exploit this vulnerability?
An unauthenticated attacker could use a specially crafted application to leverage a protocol vulnerability in the Kerberos Key Distribution Center (KDC) Proxy Service to perform denial of service against the target.

Security updates
10.0.17763.6775 — https://support.microsoft.com/help/5050008
10.0.20348.3091 — https://support.microsoft.com/help/5049983
10.0.26100.2894 — https://support.microsoft.com/help/5050009
10.0.25398.1369 — https://support.microsoft.com/help/5049984
10.0.14393.7699 — https://support.microsoft.com/help/5049993
6.2.9200.25273 — https://support.microsoft.com/help/5050004
6.3.9600.22371 — https://support.microsoft.com/help/5050048

Vulnerabilities 1

High 7.5

CVE-2025-21218

Windows Kerberos Denial of Service Vulnerability

Windows Kerberos Denial of Service Vulnerability

Microsoft Windows Server 2019 Windows Server 2019 (Server Core installation) Windows Server 2022 Windows

Jan 14, 2025

Revision history

2025-01-16 #2
Updated FAQ information. This is an informational change only.
2025-01-14 #1
Information published.

References

CVE-2025-21218 Windows Kerberos Denial of Service Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21218
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss