CVE-2026-20856
Unknown Unknown - Not Provided
Improper Input Validation in Windows Server Update Service Enables Remote Code Execution

Publication date: 2026-01-13

Last updated on: 2026-01-13

Assigner: Microsoft Corporation

Description
Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network.
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Meta Information
Published
2026-01-13
Last Modified
2026-01-13
Generated
2026-06-16
AI Q&A
2026-01-14
EPSS Evaluated
2026-06-15
NVD
CVE-2026-20856
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
microsoft windows_server_update_service *
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-20 The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
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Impact Analysis

An attacker exploiting this vulnerability can execute arbitrary code on the affected system remotely, potentially leading to full compromise of confidentiality, integrity, and availability of the system.

Executive Summary

This vulnerability is due to improper input validation in Windows Server Update Service, which allows an unauthorized attacker to execute code remotely over a network.

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