Unauthenticated Kerberos service interruption
Published Jan 14, 2025 · Updated Jun 9, 2026
Denial of service in Windows Kerberos on affected Windows Server releases allows remote attackers to interrupt authentication services. Microsoft has not published the resource or operation whose uncontrolled consumption triggers the failure. No authentication or user interaction is required; the documented effect is an availability loss without data disclosure or modification.
Summary
What happened
Denial of service in Windows Kerberos on affected Windows Server releases allows remote attackers to interrupt authentication services. Microsoft has not published the resource or operation whose uncontrolled consumption triggers the failure. No authentication or user interaction is required; the documented effect is an availability loss without data disclosure or modification.
The record
- CVE
- CVE-2025-21218
- Published
- Jan 14, 2025
- Updated
- Jun 9, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-400, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 14, 2025CVE publishedPublication date reported by the CVE source.
- Jun 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.6775
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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