Microsoft · Security update · December 9, 2025

KB5071876: December 2025 security update

KB5071876, released December 9, 2025, fixes 2 CVEs in Microsoft Exchange Server Subscription Edition RTM. None of them is reported as exploited. Patch Radar priority: High.

High
CVEs closed
2
None rated Critical
Exploited
0
None reported
Exploitation more likely
0
Vendor assessment
Highest EPSS
0.0102
63rd percentile

Priority of the 2 CVEs

Patch now 0 Urgent 0 High 1 Routine 1

Applies to

CVEs this fix closes

PriorityCVEComponentImpactCVSSEPSSExploitation
High CVE-2025-64666 Microsoft Exchange Server Elevation of Privilege 7.5 0.0102 Exploitation Less Likely
Routine CVE-2025-64667 Microsoft Exchange Server Spoofing 5.3 0.0080 Exploitation Unlikely
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