KB5077471: Fixes an elevation of privilege vulnerability

SQL Server 2017 GDR builds

KB5077471 - Description of the security update for SQL Server 2017 CU31: March 10, 2026

Summary
This security update contains fixes and resolves vulnerabilities. To learn more about the vulnerabilities, see the following security advisories:

• CVE-2026-21262 - SQL Server Elevation of Privilege Vulnerability​​​​​​​
• CVE-2026-26115 - SQL Server Elevation of Privilege Vulnerability

The Microsoft SQL Server components are updated to the following builds in this security update:

• SQL Server - product version: 14.0.3520.4, file version: 2017.140.3520.4

Improvements and fixes included in this update
A downloadable Microsoft Excel workbook that contains a summary list of builds, together with their current support lifecycle, is available. The Excel file also contains detailed fix lists. Download this Excel file now.

4973082: Fixes an elevation of privilege vulnerability in the version upgrade process for merge replication.

4916550: This hotfix blocks the ALTER USER operation if the target login is the system Administrator account.