Improper Input Validation in Windows Server Update Service Enables Tampering

Publication date: 2026-04-14

Last updated on: 2026-04-24

Assigner: Microsoft Corporation

Description

Improper input validation in Windows Server Update Service allows an unauthorized attacker to perform tampering over a network.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-04-14

Last Modified

2026-04-24

Generated

2026-07-06

AI Q&A

2026-04-14

EPSS Evaluated

2026-07-05

NVD

CVE-2026-26154

EUVD

EUVD-2026-22376

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_server_2012	r2
microsoft	windows_server_2012	*
microsoft	windows_server_2016	to 10.0.14393.9060 (exc)
microsoft	windows_server_2019	to 10.0.17763.8644 (exc)
microsoft	windows_server_2022	to 10.0.20348.5020 (exc)
microsoft	windows_server_2022_23h2	to 10.0.25398.2274 (exc)
microsoft	windows_server_2025	to 10.0.26100.32690 (exc)

Helpful Resources

Exploitability

CWE

KEV

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.

Attack-Flow Graph

Impact Analysis

The vulnerability can lead to tampering by an unauthorized attacker over a network, which may affect the integrity or availability of the Windows Server Update Service.

Executive Summary

This vulnerability is caused by improper input validation in the Windows Server Update Service. It allows an unauthorized attacker to perform tampering over a network.

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