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SQL Server 2025 GDR SQL Server 2025 GDR Security update
Patch Tuesday

KB5091223

KB5091223: Security update for SQL Server 2025, GDR branch, May 2026. Web Service Task flaw addressed; MSDASQL queries can fail

In short

Addresses one Important SQL Server vulnerability, CVE-2026-40370. Linked server queries using MSDASQL and a provider string can fail with error 7416.

Does it affect you? Applies to: SQL Server 2025 on Windows and Linux, all editions.

Build
17.0.1115.1
Servicing branch
GDR
Security
1 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

Fix 1 change

Integration Services

  • A Web Service Task vulnerability that could let an attacker read local files or cause a denial-of-service attack is addressed.1
    Addresses an XML external entity (XXE) vulnerability in the Web Service Task.

Known issues

  1. Open Affects: Everyone

    Linked server queries that use MSDASQL fail with error 7416

    Linked server queries using the MSDASQL provider and a provider string (@provstr) fail with error 7416. Stricter connection validation can reject some configurations that worked in earlier builds.2

    Workaround status No workaround yet

    Microsoft has not published a manual workaround for this issue yet. Monitor release health until a resolving update is available.

Technical details

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

Data sheet

Released
2026-05-12
Classification
Security Updates
Type
Cumulative update
Servicing branch
GDR
Restart
Required
Replaces
KB5084814, KB5077468, KB5073177
Replaced by
KB5102333
VersionBuildChannel
2025 17.0.1115.1 General availability

Security

1 vulnerability fixed
1 important
VulnerabilitySeverityCVSS
CVE-2026-40370
SQL Server Remote Code Execution Vulnerability
 Important 8.8

Downloads (Microsoft Update Catalog)

Package 2025
326.3 MB
sqlserver2025-kb5091223-x64.exe Main update · KB5091223 SHA-1: 127a2e6e…efe485

Updated components

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

Top changed componentsFiles
SQL Server Engine113
SQL Server PolyBase2

Sources

Updated
Cited passages from Microsoft's official notes (2)
  1. 1. This fix addresses an XML external entity (XXE) vulnerability in the Web Service Task that allows an attacker to read arbitrary files from the local file system or cause a denial-of-service (DoS) attack. support.microsoft.com
  2. 2. Linked server queries that use the MSDASQL (OLE DB Provider for ODBC Drivers) provider and specify a provider string (@provstr) fail and return the following error message: 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