Windows Remote Assistance: Vulnerability allows MOTW bypass

Microsoft recently released critical security updates to address the CVE-2026-20824 vulnerability , a vulnerability affecting the Windows Remote Assistance protection mechanism . The vulnerability allows the bypass of the Mark of the Web (MOTW) , a basic defense system designed to limit the execution of potentially dangerous files originating from untrusted sources.

The vulnerability was officially disclosed on January 13, 2026, and affects a wide range of Windows versions, from Windows 10 to Windows Server 2025, making it particularly important for home users and corporate environments.

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What is Mark of the Web and why does it matter?

Mark of the Web is a built-in Windows mechanism that adds metadata to files downloaded from the Internet or received via email. This way, the operating system knows that the file comes from an external source and can trigger additional security checks, such as warnings or execution restrictions.

The CVE-2026-20824 vulnerability undermines exactly this process, allowing unauthorized local attackers to defenses MOTW and manipulate files as if they came from a trusted environment.

Windows Remote Assistance Vulnerability: Technical Details and Risk

The CVE-2026-20824 vulnerability has received a score of 5.5/10 on the CVSS v3.1 scale, which indicates that it is not an immediate catastrophic threat, but neither is it a negligible risk.

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Exploitation requires local access to the system as well as some form of user interaction. However, the nature of the vulnerability poses confidentiality risks as it can be used as an intermediate stage in more complex attacks.

Which versions are affected and which updates are required

Windows 10 Version 22H2 users on 32-bit, x64, and ARM64 architectures are advised to install update KB5073724. For Windows 11, including versions 23H2, 24H2, and 25H2, updates KB5073455 or KB5074109 are required, depending on the system.

In the corporate sector, environments based on Windows Server 2019, 2022 and 2025 should proceed immediately with the installation of the corresponding patches.

All fixes have been marked as a “Required” action, indicating that the company considers the mitigation necessary for overall security.

See also: FortiSIEM: Public exploit code for critical vulnerability

Is there active exploitation?

So far, there is no evidence that the vulnerability has been actively exploited in real-world attacks. It was not publicly disclosed before the updates were released, and Microsoft rates it as "Least Likely to Exploit" due to technical difficulties that limit its widespread abuse.

However, experts warn that security vulnerabilities related to protection mechanisms are of particular importance, as they can be used to hide malware or evade detection systems based on MOTW indicators.

What organizations and users should do

Organizations are urged to integrate these updates into Windows Remote Assistance without delay. While no emergency response procedures are required, timely application of patches is considered critical to maintaining a secure environment.

For ordinary users, the message is clear: automatic Windows updates should not be ignored. Even moderately rated vulnerabilities can be links in more complex attack chains, especially in an era where threats are constantly evolving.