Privilege Elevation Vulnerability in Microsoft Windows Update Stack
CVE-2025-21204

7.8HIGH

Key Information:

Vendor: Microsoft
Status: Windows Server 2025; Windows Server 2025 (server Core Installation); Windows 10 Version 1809; Windows Server 2019
Vendor: CVE Published:; 8 April 2025

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What is CVE-2025-21204?

CVE-2025-21204 is a privilege elevation vulnerability located within the Microsoft Windows Update Stack, a critical component responsible for managing updates in Windows operating systems. This vulnerability arises from improper link resolution before file access, known as 'link following'. If exploited, an authorized attacker could leverage this flaw to gain elevated privileges on the local machine. This scenario poses a significant risk to organizations, as the compromised systems could allow attackers to execute unauthorized actions, potentially undermining the integrity and security of sensitive information and system operations.

Technical Details

The vulnerability involves a weakness in the Windows Update Stack that enables a local authorized user to manipulate link resolution processes prior to file access. This improper handling could lead to scenarios where an attacker can access files or execute commands that they would not normally have permission to, thereby elevating their privileges within the system. The technical aspects of the vulnerability suggest that it requires a certain level of access to the vulnerable system, potentially increasing the threshold for exploitation but not eliminating the risk.

Potential Impact of CVE-2025-21204

Unauthorized Privilege Escalation: Exploitation of this vulnerability allows attackers to gain elevated privileges, which could enable them to execute arbitrary commands with higher system rights than originally permitted, leading to unauthorized system control.
Data Compromise: Once elevated privileges are achieved, an attacker could access sensitive data and files, potentially compromising confidential information and posing a risk of data theft or leakage.
System Integrity Threats: The ability to conduct unauthorized actions can severely impact the integrity of the affected systems, resulting in potential disruptions of operations, implementation of malicious software, or further vulnerabilities being introduced into the network.

Affected Version(s)

Windows 10 Version 1507 32-bit Systems 10.0.10240.0 < 10.0.10240.20978

Windows 10 Version 1607 32-bit Systems 10.0.14393.0 < 10.0.14393.7969

Windows 10 Version 1809 32-bit Systems 10.0.17763.0 < 10.0.17763.7136

News Articles

BleepingComputer

CVE-2025-21204

Windows "inetpub" security fix can be abused to block future updates

A recent Windows security update that creates an 'inetpub' folder has introduced a new weakness allowing attackers to prevent the installation of future updates.

2 weeks ago

PCWorld

CVE-2025-21204

Windows 11's crucial new 'inetpub' folder is laughably easy to hack

The inetpub folder in Windows is meant to be a security measure, but attackers can block it and cause all sorts of issues due to another vulnerability.

2 weeks ago