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SQL Server 2017 GDR SQL Server 2017 GDR Security update
Patch Tuesday

KB5077472

KB5077472: Security update for SQL Server 2017, GDR branch, March 2026. Merge replication privilege flaw fixed; system Administrator protected

In short

The update fixes an elevation-of-privilege vulnerability in merge replication and blocks an ALTER USER operation targeting the system Administrator account.

Does it affect you? Applies to: Devices running SQL Server 2017 or a SQL Server 2017 GDR release, on supported x64 systems. The update applies to SQL Server on Windows and Linux; it is optional on computers that do not host Reporting Services.

Build
14.0.2100.4
Servicing branch
GDR
Security
2 fixed
Restart
Required

For servers on the GDR branch: they get security fixes only. Servers that install cumulative updates (CU branch) get a separate update. Which branch am I on?

What changes

Fixes 2 changes

Replication

For: Windows systems using merge replication

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

Security Infrastructure

For: SQL Server administrators on Linux or Windows

  • The ALTER USER operation is blocked if it targets the system Administrator account.2
    The hotfix blocks ALTER USER when the target login is the system Administrator account on Linux and Windows.

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
GDR
Restart
Required
Replaces
KB5068403, KB5065224, KB5063760, KB5058716
+4 earlier KB5046857, KB5046058, KB5042217, KB5040942
Replaced by
KB5084819
VersionBuildChannel
2017 14.0.2100.4 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 2017
452.0 MB
sqlserver2017-kb5077472-x64.exe Main update · KB5077472 SHA-1: ab44e9f3…e2f65d

Updated components

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

Top changed componentsFiles
SQL Server Engine91
SQL Server PolyBase1

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: 7 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: not passed

A second AI read the text against the sources: correctness 5/5, clarity 4/5, 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