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SQL Server 2016 SP3 AC + GDR SQL Server 2016 SP3 AC + GDR Security update
Patch Tuesday

KB5077473

KB5077473: Security update for SQL Server 2016, Azure Connect Feature Pack branch, March 2026. Merge replication privilege flaw fixed; Administrator changes blocked

In short

The update fixes two Important SQL Server vulnerabilities, including publicly disclosed CVE-2026-21262, and blocks ALTER USER operations that target the system Administrator account.

Does it affect you? Applies to: SQL Server 2016 SP3 installations with the Azure Connect Feature Pack, on supported x64-based versions. The listed fixes apply to Windows; the ALTER USER fix also applies to Linux.

Build
13.0.7075.5
Servicing branch
Azure Connect Feature Pack
Security
2 fixed
Restart
Required

For servers on the Azure Connect Feature Pack of Service Pack 3, the branch with fixes beyond security. Servers on the GDR branch (security fixes only) get a separate update. Which branch am I on?

What changes

Fixes 2 changes

Replication

  • A vulnerability in the merge replication version upgrade process is fixed.1
    Fixes an elevation-of-privilege vulnerability in the version upgrade process for merge replication.

Security Infrastructure

  • Changing a user when the target login is the system Administrator account is blocked.2
    The ALTER USER operation is blocked if the target login is the system Administrator account.

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2026-03-10
Classification
Security Updates
Type
Cumulative update
Servicing branch
Azure Connect Feature Pack
Restart
Required
Replaces
KB5068400, KB5065227, KB5063761, KB5058717
+4 earlier KB5046856, KB5046062, KB5042209, KB5040944
Replaced by
KB5084820
VersionBuildChannel
2016 13.0.7075.5 General availability

Security

2 vulnerabilities fixed
2 important
VulnerabilitySeverityCVSS
CVE-2026-21262
Microsoft SQL Server Elevation of Privilege Vulnerability
 Important 8.8
CVE-2026-26115
SQL Server Elevation of Privilege Vulnerability
 Important 8.8

Downloads (Microsoft Update Catalog)

Package 2016
507.8 MB
sqlserver2016-kb5077473-x64.exe Main update · KB5077473 SHA-1: 67d2ea04…a3d995

Updated components

515 files changed since the previous update for the same versions.

Top changed componentsFiles
SQL Server Engine77

Sources

Updated
Cited passages from Microsoft's official notes (2)
  1. 1. Fixes an elevation of privilege vulnerability in the version upgrade process for merge replication. support.microsoft.com
  2. 2. This hotfix blocks the ALTER USER operation if the target login is the system Administrator account. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 quoted passages · compared with Microsoft's page on Sep 26, 2026
  • Quotes found in the official pages: passed
  • Numbers found in the sources: passed
  • Vulnerabilities from the dossier only: passed
  • Links to allowed domains only: passed
  • Every official change covered: passed
  • Readable plain text: passed
  • Changes confirmed by the file list: passed
  • Sources agree: passed

A second AI read the text against the sources: correctness 5/5, clarity 5/5, completeness 5/5. How we work

Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake