Microsoft · Security update · August 11, 2026

KB5123303: August 2026 security update

KB5123303, released August 11, 2026, fixes 3 CVEs across 2 products. None of them is reported as exploited. Patch Radar priority: Urgent.

Urgent
CVEs closed
3
1 rated Critical
Exploited
0
None reported
Exploitation more likely
0
Microsoft's assessment
Highest EPSS
0.0033
26th percentile

Priority of the 3 CVEs

Patch now 0 Urgent 1 High 1 Routine 1

Applies to

CVEs this fix closes

PriorityCVEComponentImpactCVSSEPSSExploitation
Urgent CVE-2026-66799 Windows Key GuardElevation of Privilege7.8 0.0033 Exploitation Less Likely
High CVE-2026-6726 Windows TPMSpoofing7.9 0.0019 Exploitation Less Likely
Routine CVE-2026-6727 Windows TPMInformation Disclosure5.9 0.0015 Exploitation Less Likely
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