CVE-2018-8239: Windows GDI memory disclosure leaks information to local attacker

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 19 September 2026. Confidence: medium.

medium priorityCVSS rates it medium (5.5) with local access and user interaction required, and there is no confirmed public exploit or KEV listing despite a high EPSS score.

What it is

The Windows GDI component improperly discloses the contents of its memory, exposing data that should not be readable. It affects Windows 10, Windows 10 Servers and Windows Server 2016, and matters because leaked memory can reveal sensitive data or aid further attacks.

Impact

An attacker who triggers the flaw gains read access to memory contents handled by GDI, potentially exposing sensitive information. The CVSS vector rates confidentiality impact as high with no integrity or availability effect.

Attack surface

The vector is local (AV:L) with user interaction required (UI:R) and no privileges required (PR:N), so the attacker must get a user to open or interact with crafted content on the affected system. No network or authentication path is described.

Exploitation

CISA KEV does not list this CVE and no ransomware use is documented; EPSS is high at roughly 0.58 probability (99th percentile), but the references are only vendor advisory, patch and third-party VDB entries, so no public exploit is confirmed by this record.

What to do

• Apply the Microsoft security update referenced in the MSRC advisory for CVE-2018-8239 on all affected Windows 10 and Windows Server 2016/1803 systems.
• Prioritize patching on multi-user or high-value endpoints where local users could run crafted content.
• Restrict execution of untrusted applications and documents for non-administrative users to reduce the chance of triggering the flaw.
• Track the CVE in vulnerability management until all affected hosts report the patched build.

Detection

• Monitor for unexpected crashes or errors in GDI-related processes (for example win32k/GDI components) that could indicate malformed content being processed.
• Hunt for suspicious document or application launches by non-administrative users on affected Windows builds around the patch window.
• Review endpoint telemetry for processes reading large or unusual memory regions via GDI APIs, where such logging is available.

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