Microsoft SQL Server SQL Server 2022 Update Version 16.0.4255.1

KB5081477 delivers Cumulative Update 25 for SQL Server 2022, updating the engine to 16.0.4255.1. It includes 12 fixes, including an XXE vulnerability fix in Integration Services and several engine, HA, and Linux reliability fixes.

• Fixes an XML External Entity (XXE) vulnerability in the Web Service Task by blocking the file:// protocol in WSDL service endpoints to prevent unauthorized file access and denial-of-service attacks.

• Fixes Database Mail in Contained Availability Groups so email messages include attachments.
• Preserves permissions on stored procedures and other msdb objects during SQL Server upgrade.
• Fixes an access violation when querying sys.dm_xe_session_targets on Windows Server 2025.
• Addresses Contained Availability Group connection restrictions and T-SQL behavior for adding databases and DBCreator roles.
• Fixes a memory leak from parallel SHORTEST_PATH queries in graph databases.
• Fixes XML corruption and a subsequent transport-level error caused by self-assignment updates on compressed small off-row XML columns.
• Fixes heap corruption and possible data loss in SSIS when using the Oracle ODBC driver with the ODBC connector.
• Fixes heap corruption in the generic ODBC connector when using the Oracle ODBC driver.
• Adds yields during in-memory OLTP garbage collection scans of hash indexes to reduce CPU starvation.
• Fixes an error when online index operations run concurrently with DML in databases that have CDC enabled.
• Fixes a Linux backup cleanup issue that could cause SQL Server to stop responding when a network share becomes full or unreachable.

• Queries using SESSION_CONTEXT in parallel plans may return incorrect results or trigger access violation dump files, especially when the session is reset for reuse.
• Linked server queries using MSDASQL with a provider string may fail with error 7416 due to stricter connection validation.

• For SQL Server on Windows, Microsoft recommends enabling encryption with Extended Protection to help secure SQL Server.
• A downloadable Excel workbook provides build summaries, support lifecycle status, and detailed fix lists for SQL Server 2022, 2019, and 2017.

Product Information

Vendor: Microsoft

Product: SQL Server

Product type: Software

Variant: SQL Server 2022

Version: 16.0.4255.1

Vendor release date: May 20, 2026

Original release notes: View on vendor site

Published on updatealert.io: Aug 16, 2026