CVE & CISA-KEV Catalog

CVE-2026-66802

CRITICAL
8.1
CVSS v3
NVD

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.

CWE-362Race ConditionCWE-416Use After Free

How to fix

Remediation Available
Windows 10 Version 1809Windows
Install:KB5120238Microsoft
Windows 11 Version 26H1Windows
Install:KB5121000Microsoft
Windows 11 version 26H1Windows
Install:KB5121000Microsoft
Windows Server 2019Windows
Install:KB5120238Microsoft
Windows Server 2019 (Server Core installation)Windows
Install:KB5120238Microsoft
Windows Server 2022Windows
Install:KB5120229Microsoft
Install:KB5120242Microsoft
Windows Server 2022 (Server Core installation)Windows
Install:KB5120229Microsoft
Install:KB5120242Microsoft
Windows Server 2025Windows
Install:KB5120233Microsoft
Install:KB5120228Microsoft
Windows Server 2025 (Server Core installation)Windows
Install:KB5120228Microsoft
Install:KB5120233Microsoft

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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

Exploit Intelligence

0.36%probability of exploitation in 30 days
29thpercentile

Low risk: more likely to be exploited than 29% of all known CVEs.

References

Related Vulnerabilities

Other CWE-362 (Race Condition) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2024-6387High8.1100%-Fix
CVE-2023-36884High7.599%KEV + RansomFix
CVE-2018-15473Medium5.399%-Fix
CVE-2024-27983High8.287%-Fix
CVE-2014-0226Medium6.886%-Fix
CVE-2016-5195High7.084%KEVFix

Common questions

How do I fix CVE-2026-66802?

Published advisories record a fix for 9 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-66802 being actively exploited?

Not that we know of. CVE-2026-66802 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.36% is the estimated probability that it will be exploited in the next 30 days. That is higher than 29% of all scored CVEs.

How severe is CVE-2026-66802?

CVE-2026-66802 has a CVSS v3 base score of 8.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-66802 affect?

Published advisories record a fix for Windows 10 Version 1809 (Windows), Windows 11 Version 26H1 (Windows), Windows 11 version 26H1 (Windows), Windows Server 2019 (Windows), and 5 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-20.