Local SYSTEM privilege escalation
Published Oct 13, 2021 · Updated Oct 21, 2025
Privilege escalation in Microsoft Win32k on affected Windows releases allows local users to obtain SYSTEM privileges through a local exploit. Microsoft's public advisory identifies only the Win32k component and does not disclose the faulty routine or operation that processes attacker-controlled input. A user must already have low-privileged local access; successful exploitation crosses the Windows privilege boundary without user interaction.
Summary
What happened
Privilege escalation in Microsoft Win32k on affected Windows releases allows local users to obtain SYSTEM privileges through a local exploit. Microsoft's public advisory identifies only the Win32k component and does not disclose the faulty routine or operation that processes attacker-controlled input. A user must already have low-privileged local access; successful exploitation crosses the Windows privilege boundary without user interaction.
The record
- CVE
- CVE-2021-40450
- Published
- Oct 13, 2021
- Updated
- Oct 21, 2025
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-269, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 13, 2021CVE publishedPublication date reported by the CVE source.
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.0 <10.0.17763.2237
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- CISA Known Exploited Vulnerabilities catalog listingknown exploited catalog
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo