CVE-2016-7255: Microsoft Windows Win32k Kernel Driver Privilege Escalation

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 17 September 2026. Confidence: high.

high priorityIt is a KEV-listed kernel elevation flaw with confirmed in-the-wild and ransomware use and very high EPSS, though it requires local access and user interaction.

What it is

The kernel-mode Win32k drivers in multiple Windows versions fail to properly handle objects, letting a local user escalate privileges through a crafted application. Because the flaw sits in the kernel, successful abuse yields full system-level control and it has been exploited in the wild, making it a serious post-compromise escalation tool.

Impact

An attacker who can run code on a host gains SYSTEM-level privileges, enabling full control of the machine, credential theft, and lateral movement. It is an elevation-of-privilege primitive, not a remote entry point.

Attack surface

Reached locally by running a crafted application on an affected Windows host; the CVSS vector shows local access (AV:L) with no privileges required (PR:N) but user interaction required (UI:R). No network exposure or authentication is needed beyond the ability to execute code on the target.

Exploitation

CISA KEV lists it as actively exploited with known ransomware campaign use, EPSS is very high (0.81, 99.6th percentile), and multiple public exploit references exist, so exploitation is confirmed and tooling is widely available.

What to do

• Apply the Microsoft MS16-135 security update to all affected Windows versions immediately.
• Prioritize patching internet-facing and high-value endpoints, since this is a KEV-listed, ransomware-associated flaw.
• Restrict local code execution and application allowlisting to limit delivery of crafted applications.
• Run with least privilege and remove unnecessary local admin rights to reduce escalation value.
• Retire or isolate unsupported end-of-life Windows versions that cannot be patched.

Detection

• Monitor for unexpected processes gaining SYSTEM integrity or spawning from user contexts.
• Alert on known exploit artifacts and suspicious win32k.sys interactions tied to NtSetWindowLongPtr abuse.
• Hunt for post-exploitation behavior such as credential dumping or ransomware staging following local privilege escalation.
• Review endpoint telemetry for crafted applications executing shortly before privilege changes.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.