Summary
Impact: Security Feature Bypass. Microsoft rating: Important. Not known to be exploited — Exploitation More Likely. Customer action: Required.
Details
Are there any additional steps that I need to follow to be protected from this vulnerability?
The changes to address this vulnerability updated Virtual Secure Mode components. The policy described in Guidance for blocking rollback of Virtualization-based Security (VBS) related security updates has been updated to account for the latest changes. If you deployed this policy, then you'll need to redeploy using the updated policy.
What kind of security feature could be bypassed by successfully exploiting this vulnerability?
An attacker who successfully exploited this vulnerability could bypass Windows Defender Credential Guard Feature to leak Kerberos credentials.
Security updates
10.0.17763.6775 — https://support.microsoft.com/help/5050008
10.0.20348.3091 — https://support.microsoft.com/help/5049983
10.0.19044.5371 — https://support.microsoft.com/help/5049981
10.0.22621.4751 — https://support.microsoft.com/help/5050021
10.0.26100.2894 — https://support.microsoft.com/help/5050009
10.0.25398.1369 — https://support.microsoft.com/help/5049984
10.0.10240.20890 — https://support.microsoft.com/help/5050013
10.0.14393.7699 — https://support.microsoft.com/help/5049993
Vulnerabilities 1
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High 7.1
Windows Kerberos Security Feature Bypass Vulnerability
Windows Kerberos Security Feature Bypass Vulnerability
Revision history
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#1
Information published.
References
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CVE-2025-21299 Windows Kerberos Security Feature Bypass Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21299
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss