CVE-2020-1054: Microsoft Win32k Privilege Escalation Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 3 Nov 2021, 531 days after the CVE record was published.

How likely is exploitation in the next 30 days?

53.9%

EPSS score, percentile 99 of all scored records

How severe?

7.0 High

CVSS v3.1 base score, given by the CNA

What should I do?

CISA deadline 3 May 2022. Apply updates per vendor instructions.

Advisories and patches (1)

Which versions are affected?

Affected

• 10.0.10240.0
• 10.0.14393.0
• 10.0.0
• 10.0.0
• 10.0.0
• 10.0.17763.0

and 14 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: 3 May 2022.

Advisories and patches

• Win32k Elevation of Privilege Vulnerability (Vendor advisory, Patch)

Linked from CISA's catalog entry

• https://nvd.nist.gov/vuln/detail/CVE-2020-1054

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

Microsoft Win32k contains a privilege escalation vulnerability when the Windows kernel-mode driver fails to properly handle objects in memory. Successful exploitation allows an attacker to execute code in kernel mode.

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

• CISA added CVE-2020-1054 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
• 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 3 May 2022.
• The CVE record was published on 21 May 2020, 531 days before it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 7.0 (High), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 53.9% (percentile 99), 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

Win32k Elevation of Privilege Vulnerability

An elevation of privilege vulnerability exists in Windows when the Windows kernel-mode driver fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. The update addresses this vulnerability by correcting how the Windows kernel-mode driver handles objects in memory.

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

Weakness

• CWE-787: Out-of-bounds Write

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

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