Introduction
A heap-based buffer overflow in the Windows Win32K GRFX subsystem (CVE-2025-30388) poses a significant risk for local privilege escalation. This vulnerability, rated at a CVSS score of 7.8, allows attackers with local access to execute arbitrary code, potentially leading to full system compromise.
Affected Systems and Versions
The vulnerability specifically affects the Windows Win32K GRFX subsystem. However, detailed version information regarding affected Windows editions and builds has not been explicitly provided in the available advisories.
Technical Information
The vulnerability stems from improper memory handling within the Win32K GRFX subsystem. Specifically, the subsystem fails to adequately validate the size of user-supplied input during graphical rendering operations, resulting in a heap-based buffer overflow. This overflow enables attackers to overwrite adjacent memory structures, potentially leading to arbitrary code execution within kernel context.
Vulnerable Code Snippet (Conceptual Example)
void render_graphics(char *input, size_t size) {
char buffer[256];
memcpy(buffer, input, size); // No bounds check, potential overflow
}Attack Vectors and Exploitation Methods
Attackers require local access to exploit this vulnerability. By crafting specific graphical inputs, attackers can trigger the overflow, corrupt memory, and execute arbitrary code with elevated privileges, potentially escalating to SYSTEM-level access.
Patch Information
Microsoft has addressed this vulnerability in their May 2025 security updates. Users should immediately apply the latest patches available through Windows Update.
Detection Methods
Currently, specific detection methods, indicators of compromise, or log patterns related to CVE-2025-30388 have not been publicly disclosed.
Vendor Security History
Microsoft has previously addressed similar vulnerabilities in the Win32K subsystem, highlighting a recurring security challenge in kernel-level graphical components. Timely patching and rigorous security practices remain essential for mitigating these risks.
