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SQL Server 2019 GDR SQL Server 2019 GDR Security update
Patch Tuesday

KB5077470

KB5077470: Security update for SQL Server 2019, GDR branch, March 2026. Merge replication privilege flaw fixed; ALTER USER restricted

In short

Fixes two Important SQL Server vulnerabilities, including the publicly disclosed CVE-2026-21262, and blocks a specific ALTER USER operation.

Does it affect you? Applies to: Devices running SQL Server 2019 GDR. The listed fixes apply to Windows; the ALTER USER fix also applies to Linux.

Build
15.0.2160.4
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

  • The merge replication version upgrade process is protected against an elevation-of-privilege vulnerability.1
    Fixes the vulnerability in the version upgrade process for merge replication.

Security Infrastructure

  • ALTER USER is blocked when the target login is the system Administrator account.2
    This hotfix applies to 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
KB5068405, KB5065223, KB5063758, KB5058713
+5 earlier KB5046859, KB5046056, KB5042214, KB5040986, KB5035434
Replaced by
KB5084817
VersionBuildChannel
2019 15.0.2160.4 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 2019
507.7 MB
sqlserver2019-kb5077470-x64.exe Main update · KB5077470 SHA-1: 02f62c60…dc3d6b

Updated components

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

Top changed componentsFiles
SQL Server Engine121
SQL Server PolyBase4

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 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