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SQL Server 2025 CU4 SQL Server 2025 CU4 Cumulative update

KB5081495

KB5081495: Cumulative update for SQL Server 2025, CU branch, April 2026. Fixes lost msdb permissions and Full-Text Search failures

In short

CU4 includes 11 fixes for SQL Server 2025, including lost permissions during upgrades and failures in Full-Text Search. It also has two open known issues involving parallel SESSION_CONTEXT queries and MSDASQL linked servers.

Does it affect you? Applies to: Instances running SQL Server 2025 on Windows or Linux. The package updates only the SQL Server components that are installed on the instance.

Build
17.0.4035.5
Servicing branch
CU
Restart
Required

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

What changes

Fixes 9 changes

Database Mail

For: SQL Server instances using contained availability groups

  • Database Mail sends email attachments again when used with contained availability groups and sp_RunMailQuery.1
    Fixes the contained availability group issue with DatabaseMail and sp_RunMailQuery.

Management Services

For: Windows

  • Permissions on stored procedures and other objects in msdb are no longer unexpectedly removed during a SQL Server upgrade.2
    Applies to Windows. The issue affected permissions on msdb objects during upgrade.

SQLPAL

  • On Linux, SQL Server is less likely to stop responding because of an unintended wait on an internal thread.3
    The lock is acquired with a spin-wait on threads that don't support suspension, instead of blocking.

Integration Services

Verified in package

For: Windows

  • DTSWizard.exe opens when SQL Server is installed without the Integration Services features.4
    Applies to Windows installations without SQL Server Integration Services (SSIS).

Search

2 items
  • Indexing certain Word 6.0 documents with Full-Text Search no longer causes its filter daemon host process to stop responding.5
    The affected process is fdhost.exe.
  • Inflectional Full-Text Search queries work for version 2 languages that don't implement an IStemmer.9
    Fixes failures involving predicates such as FREETEXT, FREETEXTTABLE, and FORMSOF(INFLECTIONAL, ...).

High Availability and Disaster Recovery

For: SQL Server instances using contained availability groups

  • Contained availability groups no longer have the audit-functionality memory corruption issue.6
    Fixes a memory corruption issue in the audit functionality for contained availability groups.

SQL OS

  • Querying sys.dm_xe_session_targets no longer causes an access violation on affected Windows Server 2025 instances.7
    Applies to SQL Server instances running on Windows Server 2025.

Replication

  • Non-yielding scheduler errors and dump files that might occur during heavy lazy writer I/O are fixed.8
    Applies during a high amount of lazy writer I/O.

Improvements 2 changes

JSON

  • Json_contains uses either exact-match or pattern-match comparison, with exact match as the default.10
    The comparison mode is limited to 0 (exact match) or 1 (pattern match); the default is 0.

High Availability and Disaster Recovery

For: SQL Server instances using contained availability groups

  • Contained availability groups restrict which databases can be added. For DBCreator, the database owner must also match the logged-in user.11
    Databases can be added only to the currently connected contained availability group; DBCreator can add databases only to the current group.

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) might fail with error 7416, saying that no login mapping exists.12

    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.

  2. Open Affects: Everyone

    Incorrect behavior of SESSION_CONTEXT in parallel plans

    Queries using the built-in SESSION_CONTEXT function might return incorrect results or trigger access violation dump files when run in parallel query plans, particularly if a session is reset for reuse.13

    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
2026-04-16
Classification
Updates
Type
Cumulative update
Servicing branch
CU
Restart
Required
Replaces
KB5077896, KB5075211, KB5078298
Replaced by
KB5089899
VersionBuildChannel
2025 17.0.4035.5 General availability

Security

No vulnerabilities are listed for this update.

Downloads (Microsoft Update Catalog)

Package 2025
401.0 MB
sqlserver2025-kb5081495-x64.exe Main update · KB5081495 SHA-1: 5e462684…082cd7

Updated components

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

Top changed componentsFiles
SQL Server Engine58
SQL Server Integration Services14
SQL Server Replication12
SQL Server Agent4
SQL Server Machine Learning Services4
SQL Server Full-Text Search2
SQL Server PolyBase2
SQL Server Analysis Services1

Verified in package: changed files confirm Integration Services.

Sources

Updated
Cited passages from Microsoft's official notes (13)
  1. 1. Fixes an issue in contained availability groups that causes DatabaseMail to sends email messages without attachments when using sp_RunMailQuery. learn.microsoft.com
  2. 2. Fixes an issue in which permissions on stored procedures and other objects in msdb are lost during the SQL Server upgrade process. This issue causes unexpected permission removal for users. learn.microsoft.com
  3. 3. The lock is now acquired by using a spin-wait on such threads instead of blocking. learn.microsoft.com
  4. 4. Fixes an issue in which DTSWizard.exe doesn't open if SQL Server is installed without the SQL Server Integration Services (SSIS) features. learn.microsoft.com
  5. 5. Fixes an issue in which indexing certain Microsoft Word 6.0 documents by including Full-Text Search causes the filter daemon host process (fdhost.exe) to stop responding. learn.microsoft.com
  6. 6. Fixes a memory corruption issue in the audit functionality for contained availability groups. learn.microsoft.com
  7. 7. Fixes an access violation error that occurs when you query sys.dm_xe_session_targets for instances that run on Windows Server 2025. learn.microsoft.com
  8. 8. Fixes non-yielding scheduler errors and dump files that might occur during a high amount of lazy writer I/O. learn.microsoft.com
  9. 9. Fixes an issue in which inflectional Full-Text Search queries fail for version 2 languages that do not implement an IStemmer. learn.microsoft.com
  10. 10. Limits the comparison mode for Json_contains to a value of either 0 (exact match) or 1 (pattern match). The default value is 0. learn.microsoft.com
  11. 11. For contained availability groups (CAG), restricts adding databases to only the currently connected CAG. For DBCreator, restricts adding databases to only the current CAG, and requires the database owner to match the logged-in user. learn.microsoft.com
  12. 12. 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: learn.microsoft.com
  13. 13. Queries that use the built-in SESSION_CONTEXT function might return incorrect results or trigger access violation (AV) dump files when run in parallel query plans. learn.microsoft.com
Checked automatically: 8 of 8 checks passed, 13 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 4/5, 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