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CVE-2021-40450

Microsoft Win32k Privilege Escalation

7.8 HIGHActively exploited (CISA KEV)EPSS 1.58%
  1. Published12 Oct 2021
  2. Added to CISA KEV25 Apr 2022
  3. Remediation due16 May 2022
Actively exploited (CISA KEV)

Microsoft Win32k contains an unspecified vulnerability that allows for privilege escalation.

Added to KEV: 25 Apr 2022Federal remediation due: 16 May 2022

Description

Win32k Elevation of Privilege Vulnerability

CVSS 3.1 breakdown

Attack vectorLocal
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft Windows 10 1809< 10.0.17763.2237
Microsoft Windows 10 1909< 10.0.18363.1854
Microsoft Windows 10 2004< 10.0.19041.1288
Microsoft Windows 10 20h2< 10.0.19042.1288
Microsoft Windows 10 21h1< 10.0.19043.1288
Microsoft Windows 11 21h2< 10.0.22000.258
Microsoft Windows Server 2004< 10.0.19041.1288
Microsoft Windows Server 2019< 10.0.17763.2237
Microsoft Windows Server 2022< 10.0.20348.288
Microsoft Windows Server 20h2< 10.0.19042.1288

Remediation

Fixed in
Microsoft Windows 10 1809≥ 10.0.17763.2237
Microsoft Windows 10 1909≥ 10.0.18363.1854
Microsoft Windows 10 2004≥ 10.0.19041.1288
Microsoft Windows 10 20h2≥ 10.0.19042.1288
Microsoft Windows 10 21h1≥ 10.0.19043.1288
Microsoft Windows 11 21h2≥ 10.0.22000.258
Microsoft Windows Server 2004≥ 10.0.19041.1288
Microsoft Windows Server 2019≥ 10.0.17763.2237
Microsoft Windows Server 2022≥ 10.0.20348.288
Microsoft Windows Server 20h2≥ 10.0.19042.1288

References

Frequently asked

Is CVE-2021-40450 being actively exploited?

Yes. CVE-2021-40450 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 25 Apr 2022.

How severe is CVE-2021-40450?

CVE-2021-40450 has a CVSS 3.1 base score of 7.8, rated high. EPSS estimates a 1.58% probability of exploitation.

Which products are affected by CVE-2021-40450?

Affected products include Microsoft Windows 10 1809, Microsoft Windows 10 1909, Microsoft Windows 10 2004, Microsoft Windows 10 20h2, Microsoft Windows 10 21h1, and 5 more.

How do I fix CVE-2021-40450?

Upgrade affected software to a fixed version, for example Microsoft Windows 10 1809 10.0.17763.2237, Microsoft Windows 10 1909 10.0.18363.1854, Microsoft Windows 10 2004 10.0.19041.1288 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-40450 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.