CVE-2026-20839: Windows Client-Side Caching (CSC) Service Information Disclosure Vulnerability
Improper access control in Windows Client-Side Caching (CSC) Service allows an authorized attacker to disclose information locally.
Other sources
Windows Client-Side Caching (CSC) Service Information Disclosure Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.3.9600.22968Patch KB5073696 - Upgrade
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Fixed in 10.0.14393.8783Patch KB5073722 - Upgrade
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Fixed in 6.2.9200.25868Patch KB5073698 - Upgrade
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Fixed in 6.1.7601.28117Patch KB5073699 - Upgrade
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Fixed in 10.0.26100.7623Patch KB5074109 - Upgrade
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Fixed in 10.0.26100.32230Patch KB5073379 - Upgrade
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Fixed in 10.0.25398.2092Patch KB5073450 - Upgrade
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Fixed in 10.0.22631.6491Patch KB5073455 - Upgrade
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Fixed in 10.0.26200.7623Patch KB5074109 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.19045.6809Patch KB5073724 - Upgrade
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Fixed in 10.0.19044.6809Patch KB5073724 - Upgrade
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Fixed in 10.0.20348.4648Patch KB5073457 - Upgrade
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Fixed in 10.0.17763.8276Patch KB5073723
Event History
Frequently Asked Questions
What is the severity of CVE-2026-20839?
CVE-2026-20839 has a severity rating of High, indicating significant risk of information disclosure if exploited.
How do I fix CVE-2026-20839?
To fix CVE-2026-20839, apply the latest available patches provided by Microsoft for the affected software versions.
What impact does CVE-2026-20839 have on my system?
CVE-2026-20839 allows an authorized attacker to disclose sensitive information stored in the Windows Client-Side Caching Service.
Which software versions are affected by CVE-2026-20839?
CVE-2026-20839 affects multiple versions of Windows including Windows Server 2008 R2, Windows Server 2012, and Windows 10.
Is there a workaround for CVE-2026-20839?
There are no documented workarounds for CVE-2026-20839, thus applying updates is critical for mitigation.