Microsoft Windows up to Server 2025 Win32k type confusion

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.1$5k-$25k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Microsoft Windows up to Server 2025. Affected by this vulnerability is an unknown functionality of the component Win32k. This manipulation causes type confusion. This vulnerability is tracked as CVE-2026-20811. The attack is restricted to local execution. No exploit exists. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability was found in Microsoft Windows up to Server 2025. It has been declared as critical. Affected by this vulnerability is an unknown functionality of the component Win32k. The manipulation with an unknown input leads to a type confusion vulnerability. The CWE definition for the vulnerability is CWE-843. The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Access of resource using incompatible type ('type confusion') in Windows Win32K - ICOMP allows an authorized attacker to elevate privileges locally.

The weakness was disclosed 01/13/2026 as confirmed security update guide (Website). It is possible to read the advisory at msrc.microsoft.com. This vulnerability is known as CVE-2026-20811. The exploitation appears to be easy. Attacking locally is a requirement. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 01/19/2026).

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-0083). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Microsoft Windows 11
  • Microsoft Windows Server 2016
  • Microsoft Windows 10
  • Microsoft Windows Server 2019
  • Microsoft Windows Server 2022
  • Microsoft Windows Server 2025
  • Microsoft Windows Server
  • Microsoft Windows Server 2012
  • Microsoft Windows Server 2012 R2

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.8
VulDB Meta Temp Score: 7.1

VulDB Base Score: 7.8
VulDB Temp Score: 6.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 7.8
Vendor Vector (Microsoft): 🔒

CNA Base Score: 7.8
CNA Vector (Microsoft): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Type confusion
CWE: CWE-843
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Unproven

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔒
0-Day Time: 🔒
Exposure Time: 🔒

Timelineinfo

01/13/2026 VulDB entry created
01/13/2026 +0 days Advisory disclosed
01/13/2026 +0 days Countermeasure disclosed
01/19/2026 +6 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-20811 (🔒)
GCVE (CVE): GCVE-0-2026-20811
GCVE (VulDB): GCVE-100-340747
CERT Bund: WID-SEC-2026-0083 - Microsoft Windows : Mehrere Schwachstellen

Entryinfo

Created: 01/13/2026 19:14
Updated: 01/19/2026 10:53
Changes: 01/13/2026 19:14 (32), 01/13/2026 19:15 (4), 01/13/2026 19:18 (33), 01/16/2026 07:21 (11), 01/19/2026 10:53 (7)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion

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