Summary
Impact: Information Disclosure. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation of this vulnerability requires an attacker to carefully time their actions to exploit the timing differences in the execution of specific operations. They must accurately measure these timing variations to infer sensitive information or gain unauthorized access. This often involves sophisticated techniques to manipulate and observe the timing behavior of the target system.
According to the CVSS metric, successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability?
An attacker who successfully exploited this vulnerability could potentially execute a cross-VM attack, thereby compromising multiple virtual machines and expanding the impact of the attack beyond the initially targeted VM.
What type of information could be disclosed by this vulnerability?
The type of information that could be disclosed if an attacker successfully exploited this vulnerability is the contents of encrypted PKCS1 information. An attacker could read the contents of encrypted PKCS1 information from a user mode process.
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.
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
6.0.6003.23070 — https://support.microsoft.com/help/5050063
6.0.6003.23070 — https://support.microsoft.com/help/5050061
6.1.7601.27520 — https://support.microsoft.com/help/5050049
6.1.7601.27520 — https://support.microsoft.com/help/5050006
6.2.9200.25273 — https://support.microsoft.com/help/5050004
6.3.9600.22371 — https://support.microsoft.com/help/5050048
Vulnerabilities 1
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Medium 5.6
Windows Cryptographic Information Disclosure Vulnerability
Windows Cryptographic Information Disclosure Vulnerability
Revision history
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#2
Updated CWE value. This is an informational change only.
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#1
Information published.
References
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CVE-2025-21336 Windows Cryptographic Information Disclosure Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21336
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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