Microsoft Windows 10 22H2/11 24H2/11 25H2/11 26H1 access control

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.4$5k-$25k1.21-

Summaryinfo

A vulnerability classified as very critical has been found in Microsoft Windows 10 22H2/11 24H2/11 25H2/11 26H1. Affected is an unknown function. This manipulation causes access control. The identification of this vulnerability is CVE-2026-66804. The attack can only be executed locally. There is no exploit available.

Detailsinfo

A vulnerability has been found in Microsoft Windows 10 22H2/11 24H2/11 25H2/11 26H1 and classified as very critical. Affected by this vulnerability is some unknown processing. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Improper access control in Windows Cross Device Service allows an authorized attacker to elevate privileges locally.

The advisory is shared at msrc.microsoft.com. This vulnerability is known as CVE-2026-66804 since 07/27/2026. The exploitation appears to be easy. An attack has to be approached locally. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/12/2026). MITRE ATT&CK project uses the attack technique T1068 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Timelineinfo

07/27/2026 CVE reserved
08/11/2026 +15 days VulDB entry created
08/12/2026 +0 days Advisory disclosed
08/12/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-66804 (🔒)
GCVE (CVE): GCVE-0-2026-66804
GCVE (VulDB): GCVE-100-388849
scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 08/12/2026 00:51
Changes: 08/12/2026 00:51 (53)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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