Microsoft Desktop Windows Manager Out-Of-Bounds Vulnerability Let Attackers Escalate Privileges

Microsoft has acknowledged a significant out-of-bounds vulnerability within the Desktop Window Manager (DWM), which poses a serious risk by enabling local attackers to escalate their privileges to SYSTEM on affected Windows systems.

This vulnerability, designated as CVE-2025-55681, is embedded in the dwmcore.dll component and affects a wide range of Windows operating systems, including Windows 10, Windows 11, and various server editions globally.

Understanding the Vulnerability

The flaw is traced back to the CBrushRenderingGraphBuilder::AddEffectBrush function within the DWM core library, a vital component responsible for rendering visual effects and managing graphics operations.

Once local access to an affected system is achieved, attackers can exploit improper buffer handling to execute code with elevated privileges. This vulnerability does not necessitate user interaction, heightening its threat level, especially in enterprise environments where systems are often shared among multiple users or accessed remotely.

During the TyphoonPWN Windows security competition, security researchers showcased the vulnerability, highlighting its exploitation reliability. With a CVSS v3.1 score of 7.8, this vulnerability is classified as high severity. An authenticated attacker with minimal user privileges can circumvent security measures and gain unrestricted access to the system, facilitating the installation of malware, alteration of system configurations, or theft of sensitive information.

Although the exploit operates most effectively on Windows 11 systems, it remains functional on Windows 10, albeit with diminished stability due to differing heap memory management implementations in older versions. In response, Microsoft has rolled out security patches as part of its routine updates.

According to reports from SSD-Disclosure, organizations are urged to apply these patches promptly across all affected Windows systems. Until the patches are installed, administrators should implement stringent access controls to limit opportunities for local code execution, disable unnecessary services, and adhere to the principle of least privilege for user accounts.

System administrators are strongly encouraged to prioritize the deployment of this critical update, given the severe implications of privilege escalation and the low complexity required for exploitation.

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