CVE-2018-8589: Microsoft Win32k Privilege Escalation Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 23 May 2022, 1,286 days after the CVE record was published.

How likely is exploitation in the next 30 days?

3%

EPSS score, percentile 87.4 of all scored records

How severe?

7.8 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA deadline 13 Jun 2022. Apply updates per vendor instructions.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• 32-bit Systems Service Pack 2
• 32-bit Systems Service Pack 2 (Server Core installation)
• Itanium-Based Systems Service Pack 2
• x64-based Systems Service Pack 2
• x64-based Systems Service Pack 2 (Server Core installation)
• 32-bit Systems Service Pack 1

and 4 more in the table below

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 13 June 2022.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

• https://nvd.nist.gov/vuln/detail/CVE-2018-8589

Affected products and versions

As listed in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

A privilege escalation vulnerability exists when Windows improperly handles calls to Win32k.sys. An attacker who successfully exploited this vulnerability could run remote code in the security context of the local system.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2018-8589 to its Known Exploited Vulnerabilities (KEV) catalog on 23 May 2022.
• CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
• The due date CISA sets for the required action is 13 Jun 2022.
• The CVE record was published on 14 Nov 2018, 1,286 days before it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 7.8 (High), taken from CISA's enrichment of the record.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 3% (percentile 87.4), as of 28 Oct 2026.
• CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

An elevation of privilege vulnerability exists when Windows improperly handles calls to Win32k.sys, aka "Windows Win32k Elevation of Privilege Vulnerability." This affects Windows Server 2008, Windows 7, Windows Server 2008 R2.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Timeline

References

• 105796 (Vulnerability database)
• 1042140 (Vulnerability database)
• portal.msrc.microsoft.com

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