CVE-2021-1732
HIGH
2021-02-25
[email protected]
7.8
CVSS 3.1
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CVSS Vector
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
5
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
Tags
Description
Windows Win32k Elevation of Privilege Vulnerability
Analysis
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 Context
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 Products
['Microsoft Windows 10 (multiple versions)', 'Microsoft Windows Server 2019/2004/20H2']
Remediation
Apply Microsoft security update. Deploy Win32k syscall filtering via Windows Defender Exploit Guard ASR rules.
Priority Score
209
Low
Medium
High
Critical
KEV: +50
EPSS: +90.1
CVSS: +39
POC: +20
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External POC / Exploit Code
Leaving vuln.today
Destination URL
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