Microsoft Windows up to Server 2025 Win32k race condition

CVSS Meta Temp Score
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CTI Interest Score
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6.1$5k-$25k0.00

Summaryinfo

A vulnerability was found in Microsoft Windows. It has been rated as critical. The impacted element is an unknown function of the component Win32k. This manipulation causes race condition. The identification of this vulnerability is CVE-2026-34331. The attack can only be executed locally. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Microsoft Windows. It has been declared as critical. Affected by this vulnerability is an unknown function of the component Win32k. The manipulation with an unknown input leads to a race condition vulnerability. The CWE definition for the vulnerability is CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was shared 05/12/2026 as confirmed security update guide (Website). It is possible to read the advisory at msrc.microsoft.com. This vulnerability is known as CVE-2026-34331. The exploitation appears to be difficult. 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 05/15/2026).

Upgrading to version 10.0.17763.8755 eliminates this vulnerability. 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-2026-1489). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

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

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.0
VulDB Meta Temp Score: 6.1

VulDB Base Score: 7.0
VulDB Temp Score: 6.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 7.0
Vendor Vector (Microsoft): 🔒

CVSSv2info

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

Exploitinginfo

Class: Race condition
CWE: CWE-362
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: Upgrade
Status: 🔍

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

Upgrade: Windows 10.0.17763.8755

Timelineinfo

05/12/2026 VulDB entry created
05/12/2026 +0 days Advisory disclosed
05/12/2026 +0 days Countermeasure disclosed
05/15/2026 +2 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-34331 (🔒)
GCVE (CVE): GCVE-0-2026-34331
GCVE (VulDB): GCVE-100-363139
CERT Bund: WID-SEC-2026-1489 - Microsoft Windows Produkte: Mehrere Schwachstellen

scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 05/12/2026 19:19
Updated: 05/15/2026 08:33
Changes: 05/12/2026 19:19 (37), 05/12/2026 19:22 (33), 05/15/2026 08:33 (6)
Complete: 🔍
Cache ID: 216::103

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

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