Microsoft Windows up to Server 2025 Ancillary Function Driver for WinSock race condition

CVSS Meta Temp Score
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CTI Interest Score
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6.4$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Microsoft Windows. This impacts an unknown function of the component Ancillary Function Driver for WinSock. This manipulation causes race condition. This vulnerability appears as CVE-2025-49762. The attack requires local access. There is no available exploit. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability has been found in Microsoft Windows and classified as critical. Affected by this vulnerability is an unknown code of the component Ancillary Function Driver for WinSock. 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 summary by CVE is:

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

The weakness was presented 08/12/2025 as confirmed security update guide (Website). It is possible to read the advisory at msrc.microsoft.com. This vulnerability is known as CVE-2025-49762. 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 $0-$5k at the moment (estimation calculated on 11/21/2025).

The vulnerability scanner Nessus provides a plugin with the ID 249135 (KB5063948: Windows Server 2008 Security Update (August 2025)), which helps to determine the existence of the flaw in a target environment.

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 databases at Tenable (249135) and CERT Bund (WID-SEC-2025-1790). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Hitachi Virtual Storage Platform
  • Microsoft Windows Server 2022
  • Microsoft Windows Server
  • Microsoft Windows 10
  • Microsoft Windows Server 2016
  • Microsoft Windows Server 2019
  • Microsoft Windows 11
  • Microsoft Windows Server 2012
  • Microsoft Windows Server 2012 R2
  • Microsoft Windows Server 2025
  • Microsoft Windows

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: 6.4

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

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

CNA Base Score: 7.0
CNA 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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Nessus ID: 249135
Nessus Name: KB5063948: Windows Server 2008 Security Update (August 2025)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

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

Timelineinfo

08/12/2025 VulDB entry created
08/12/2025 +0 days Advisory disclosed
08/12/2025 +0 days Countermeasure disclosed
11/21/2025 +101 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2025-49762 (🔒)
GCVE (CVE): GCVE-0-2025-49762
GCVE (VulDB): GCVE-100-319603
CERT Bund: WID-SEC-2025-1790 - Microsoft Windows und Windows Server: Mehrere Schwachstellen

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

Entryinfo

Created: 08/12/2025 19:22
Updated: 11/21/2025 11:41
Changes: 08/12/2025 19:22 (35), 08/12/2025 19:26 (34), 08/13/2025 06:20 (2), 08/20/2025 03:28 (12), 11/21/2025 11:41 (7)
Complete: 🔍
Cache ID: 216::103

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

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