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The Update Bureau

Monthly Patch Briefing

October 2026

76 updates released this month .

Updates, page 4

Updates, page 4:
  • Exchange Server · CU23
    Exchange Server 2016 CU23 Exchange Server 2016 CU23 ESU only Out-of-band security update
    Out-of-band
    KB5129958

    Shared mailbox wrapper messages fixed; published calendars can fail

    Fixes wrapper messages appearing in shared mailboxes in hybrid environments. Published calendar subscriptions can still return HTTP 500; KB5128898 later resolves the issue for Exchange Server 2016 CU23.

    Build 15.1.2507.75
    Security 9 CVEs
    Known issues 1 open
    Replaced by KB5128898 →