What is the CVSS score of CVE-2021-1732?

CVE-2021-1732 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 90.1%.

Which versions of Windows are affected by CVE-2021-1732?

CVE-2021-1732 presents notable security risk, a out-of-bounds write vulnerability rated CVSS 7.8.. A patch is available.

Is there a public PoC exploit available for CVE-2021-1732?

Yes, a public proof-of-concept exploit is available for CVE-2021-1732. Prioritise patching immediately. EPSS: 90.1%.

How to fix or mitigate CVE-2021-1732?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. If patching is delayed, consider network segmentation to limit exposure.

Windows CVE-2021-1732

HIGH

Out-of-bounds Write (CWE-787)

2021-02-25 secure@microsoft.com

Windows

7.8

CVSS 3.1

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 26, 2026 - 11:19 vuln.today

Added to CISA KEV

Oct 30, 2025 - 19:56 cisa

CISA KEV

PoC Detected

Oct 30, 2025 - 19:56 vuln.today

Public exploit code

Patch released

Oct 30, 2025 - 19:56 nvd

Patch available

CVE Published

Feb 25, 2021 - 23:15 nvd

HIGH 7.8

DescriptionNVD

Windows Win32k Elevation of Privilege Vulnerability

AnalysisAI

Windows Win32k contains an out-of-bounds write vulnerability enabling local privilege escalation to SYSTEM, exploited by the Bitter APT group in February 2021 for targeted espionage operations.

Technical ContextAI

The CWE-787 out-of-bounds write in win32k.sys occurs during processing of specific window message operations. The kernel write primitive enables token manipulation for privilege escalation from any user context to SYSTEM.

Affected ProductsAI

Microsoft Windows 10 (multiple versions) Microsoft Windows Server 2019/2004/20H2

RemediationAI

Apply Microsoft security update. Deploy Win32k syscall filtering via Windows Defender Exploit Guard ASR rules.

CVE-2021-1732 vulnerability details – vuln.today

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Windows CVE-2021-1732

CVSS VectorNVD

Lifecycle Timeline

DescriptionNVD

AnalysisAI

Technical ContextAI

Affected ProductsAI

RemediationAI

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External POC / Exploit Code