CVE-2017-0263: Microsoft Windows Win32k use-after-free 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 kernel privilege-escalation flaw with public exploit code and KEV listing, but it requires an existing local foothold and affects largely legacy Windows versions.

What it is

The Win32k kernel-mode drivers in multiple Windows versions contain a use-after-free (CWE-416) that lets a local user escalate privileges by running a crafted application. Because the flaw sits in the kernel, successful exploitation yields full control of the affected host, making it a standard post-compromise escalation step.

Impact

An attacker who already has code execution as a low-privileged local user can gain elevated privileges, typically SYSTEM, on the target machine. That access enables credential theft, disabling of security controls, and lateral movement.

Attack surface

Reached locally: the CVSS vector is AV:L with PR:L and UI:N, so the attacker needs an existing low-privileged account or session on the host and no user interaction. No network or remote vector is described.

Exploitation

It is listed in CISA KEV (added 2022-02-10) and public exploit code exists per Exploit-DB and third-party references; EPSS 30-day probability is about 10% (95th percentile). CISA records no known ransomware campaign use.

What to do

• Apply the Microsoft security update referenced in the MSRC advisory for CVE-2017-0263 on all affected Windows versions.
• Prioritize patching of Windows 7 SP1, Windows 8.1, Windows RT 8.1, Windows Server 2008 SP2/R2 SP1, Windows Server 2012/R2, and Windows Server 2016, plus Windows 10 Gold through 1703.
• Restrict and monitor local interactive logon and RDP access so untrusted users cannot obtain the low-privileged session the exploit requires.
• Where legacy systems cannot be patched, isolate them and limit the accounts and applications permitted to run on them.

Detection

• Alert on unexpected child processes spawning from Office, browsers, or other user-facing applications, which is a common pattern for local privilege-escalation exploits.
• Monitor for processes gaining SYSTEM or high-integrity tokens shortly after a low-privileged process starts.
• Hunt for known public exploit binaries or scripts matching the Exploit-DB 44478 pattern on endpoints.
• Review Windows kernel and Win32k-related crash or bugcheck telemetry for signs of use-after-free exploitation attempts.

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