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VulnerabilityPublished Updated

CVE-2026-66802: Microsoft Windows 10 Version 1809 · Race Condition

Affects Microsoft Windows 10 Version 1809Source CVE Database V5

0

Not known to be exploited · CVSS 8.1 High : upgrade to 10.0.17763.9121 soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 10.0.17763.9121, 10.0.28000.2704, 10.0.20348.5499 +1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
MicrosoftWindows 10 Version 1809Affected
  • >=10.0.17763.0 <10.0.17763.9121
Fixed in
  • 10.0.17763.9121
MicrosoftWindows 11 version 26H1Affected
  • >=10.0.28000.0 <10.0.28000.2704
Fixed in
  • 10.0.28000.2704
MicrosoftWindows Server 2019Affected
  • >=10.0.17763.0 <10.0.17763.9121
Fixed in
  • 10.0.17763.9121
MicrosoftWindows Server 2019 (Server Core installation)Affected
  • >=10.0.17763.0 <10.0.17763.9121
Fixed in
  • 10.0.17763.9121
MicrosoftWindows Server 2022Affected
  • >=10.0.20348.0 <10.0.20348.5499
Fixed in
  • 10.0.20348.5499
MicrosoftWindows Server 2025Affected
  • >=10.0.26100.0 <10.0.26100.33296
Fixed in
  • 10.0.26100.33296

AI-suggested

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages remediation server-side. Users and administrators should apply the official update as directed in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66802 to mitigate this vulnerability.

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Device Health Attestation (DHA) allows an unauthorized attacker to execute code over a network.

References

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