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Microsoft Security Response CenterCVE-2026-69375

Microsoft Exchange Server Tampering Vulnerability

HighVendor CVSS 6.5 / 10 1 CVE Published Sep 8, 2026 at 7:00 AM UTC

Summary

Authorization bypass through user-controlled key in Microsoft Exchange Server allows an authorized attacker to perform tampering over a network.

Products covered

  • Microsoft Exchange Server Subscription Edition RTM

  • Microsoft Exchange Server 2019 Cumulative Update 15

  • Microsoft Exchange Server 2016 Cumulative Update 23

  • Microsoft Exchange Server 2019 Cumulative Update 14

Remediation

Install KB5121608. Install KB5121609. Install KB5121611. Install KB5121610.

Vendor-listed fixes

  • 15.02.2562.049

  • 15.02.1748.051

  • 15.01.2507.073

  • 15.02.1544.046

CVEs in this advisory 1

Updates

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Confirmed at the source

    Our collector saw this advisory during a later source check.