CVE-2026-66804Public exploit

SYSTEM escalation via missing-path DLL planting

Published Aug 11, 2026 · Updated Aug 25, 2026

Improper access control in Windows Cross Device Service in Windows 10 22H2 and Windows 11 24H2 through 26H1 lets local users gain SYSTEM. A machine-wide COM registration points the Cross Device virtual-camera server to %PROGRAMDATA%\CrossDevice\CrossDevice.Streaming.Source.dll, but vulnerable systems can expose that path before the directory exists, letting a low-privileged user create it and plant a malicious DLL that Windows Camera Frame Server loads as LOCAL SERVICE. Exploitation requires local code execution and the missing-path state; the published proof chain then uses the service token's SeImpersonatePrivilege to escalate from a standard account to SYSTEM.

CVSS severity7.8
High
EPSS probability5.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Windows Cross Device Service in Windows 10 22H2 and Windows 11 24H2 through 26H1 lets local users gain SYSTEM. A machine-wide COM registration points the Cross Device virtual-camera server to %PROGRAMDATA%\CrossDevice\CrossDevice.Streaming.Source.dll, but vulnerable systems can expose that path before the directory exists, letting a low-privileged user create it and plant a malicious DLL that Windows Camera Frame Server loads as LOCAL SERVICE. Exploitation requires local code execution and the missing-path state; the published proof chain then uses the service token's SeImpersonatePrivilege to escalate from a standard account to SYSTEM.

The record

CVE
CVE-2026-66804
Published
Aug 11, 2026
Updated
Aug 25, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-284, T1546.015
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8GitHub Advisory DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-284Improper Access Control
T1546.015Component Object Model Hijacking

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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