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SQL Server 2022 CU23 SQL Server 2022 CU23 Cumulative update

KB5078297

KB5078297: Cumulative update for SQL Server 2022, CU branch, January 2026. Database Mail restored; parallel SESSION_CONTEXT issue remains

In short

CU23 restores Database Mail functionality broken by the initial release and includes 15 fixes. Queries using SESSION_CONTEXT in parallel plans can still return incorrect results or trigger access violation dumps.

Does it affect you? Applies to: SQL Server 2022 on Windows and Linux. The package updates only the SQL Server components already installed on the instance.

Build
16.0.4236.2
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 13 changes

Backup Restore

For: SQL Server instances using the SIMPLE recovery model

  • Backup log operations no longer fail with an error saying that BACKUP LOG is not allowed when the recovery model is SIMPLE.1
    Fixes the BACKUP LOG failure when the recovery model is SIMPLE.

High Availability and Disaster Recovery

2 items
  • An assertion issue related to new log readiness notifications is fixed.2
    Fixes an AV assertion issue in DbMgrPartner related to new log readiness notifications.
  • Distributed Availability Group seeding no longer fails when the local Availability Group is offline.7
    Fixes Distributed Availability Group seeding when the local Availability Group is offline.

Protocols

For: All platforms

  • Non-yielding scheduler dump files are no longer generated when SSL connections close under high CPU load.3
    Fixes generation of non-yielding scheduler dump files when SSL connections close under high CPU load.

Programmability

2 items
  • Upgrading from SQL Server 2019 to SQL Server 2022 no longer gets stuck during the model database upgrade phase.4
    Fixes an upgrade hang during the model database upgrade phase.
  • A missing partition in a common table expression no longer causes a crash.9
    Fixes a crash caused by a missing partition in a common table expression (CTE).

Linux

3 items

For: Linux

  • SQL Server no longer crashes if the Domain Controller returns an invalid ID type in LookupAccountSid.5
    Fixes crashes when an invalid ID type is returned from the Domain Controller in LookupAccountSid.
  • Active Directory logins work when the keytab file is updated too long after the privileged user password is rotated.6
    Fixes an issue that prevents Active Directory logins when the keytab file is updated too long after the privileged user password is rotated.
  • VDI restore operations no longer fail to allocate memory when memory is limited through cgroupsv2.10
    Fixes memory allocation failure during VDI restore operations when memory is limited through cgroupsv2.

Security Infrastructure

For: All platforms

  • Configuring multiple concurrent auditing operations to write to the Security Event log no longer fails during updates.8
    Fixes a failure to configure multiple concurrent auditing to write to the Security Event log during updates.

Certificate Import

For: Windows

  • SQL Server Configuration Manager imports the affected certificates without failing.11
    Fixes certificate import failures in SSCM, including password-protected self-signed certificates and certificates exported from Azure AKV that aren't password protected.

Query Execution

For: All platforms

  • AppDomains in a DOOMED state are unloaded correctly.12
    Fixes AppDomains in a DOOMED state not being unloaded correctly.

Database Mail

For: SQL Server 2022 instances with the initial CU23 release installed

  • Database Mail functionality is restored in the current CU23 release; the initial release could stop Database Mail from working.13
    The issue affected product version 16.0.4235.2 and file version 2022.160.4235.2. Email queued through Database Mail while the initial release was installed isn't automatically resent after uninstalling it or installing a cumulative update with the fix.

Improvements 2 changes

High Availability and Disaster Recovery

For: All platforms

  • Creating an availability group with a name longer than 64 characters returns error 19544 instead of an assertion when cluster_type is NONE or EXTERNAL.14
    Changes behavior for availability groups created with cluster_type = NONE or EXTERNAL and names longer than 64 characters.

Security Infrastructure

For: All platforms

  • Only sysadmins can invoke dbcc stackdump to create a dump file.15
    Restricts privileges for dbcc stackdump so that only the sysadmin can invoke the dump file.

New feature 1 change

SQL OS

  • Azure SQL Managed Instance can use sys.fn_xe_file_target_read_file() to read system_health event session data.16
    Enables sys.fn_xe_file_target_read_file() to read system_health event session data in Azure SQL Managed Instance.

Known issues

  1. Open Affects: Everyone

    Incorrect behavior of SESSION_CONTEXT in parallel plans

    Queries using SESSION_CONTEXT might return incorrect results or trigger access violation dump files when run in parallel query plans, particularly if the session is reset for reuse.17

    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
2026-01-29
Classification
Updates
Type
Cumulative update
Servicing branch
CU
Restart
Required
Replaces
KB5068450, KB5065865, KB5059390, KB5054531
+8 earlier KB5050771, KB5048038, KB5048033, KB5041321, KB5038325, KB5036432, KB5033663, KB5032679
Replaced by
KB5077464
VersionBuildChannel
2022 16.0.4236.2 General availability

Security

No vulnerabilities are listed for this update.

Downloads (Microsoft Update Catalog)

Package 2022
464.4 MB
sqlserver2022-kb5078297-x64.exe Main update · KB5078297 SHA-1: 7804e768…c67c0d

Updated components

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

Top changed componentsFiles
SQL Server Engine30
SQL Server Replication13
SQL Server Integration Services10
SQL Server Agent5
SQL Server Machine Learning Services4
SQL Server Full-Text Search2
SQL Server PolyBase2

Sources

Updated
Cited passages from Microsoft's official notes (17)
  1. 1. Fixes an issue in which backup log operations fail and return an error that indicates that BACKUP LOG is not allowed while the recovery model is SIMPLE. learn.microsoft.com
  2. 2. Fixes an AV assertion issue in DbMgrPartner that's related to new log readiness notifications. learn.microsoft.com
  3. 3. Fixes an issue in which non-yielding scheduler dump files are generated when SSL connections are closed under high CPU load. learn.microsoft.com
  4. 4. Fixes an issue in which upgrading from SQL Server 2019 to SQL Server 2022 might cause the upgrade process to stop responding during the model database upgrade phase. learn.microsoft.com
  5. 5. Fixes an issue that causes crashes when an invalid ID type is returned from the Domain Controller in LookupAccountSid. learn.microsoft.com
  6. 6. Fixes an issue that prevents Active Directory logins from working if the keytab file is updated too long after the privileged user password is rotated. learn.microsoft.com
  7. 7. Fixes an issue in which Distributed Availability Group seeding fails if the local Availability Group is offline. learn.microsoft.com
  8. 8. Fixes a failure to configure multiple concurrent auditing to write to the Security Event log during updates. learn.microsoft.com
  9. 9. Fixes a crash that's caused by a missing partition in a common table expression (CTE). learn.microsoft.com
  10. 10. Fixes a bug that causes memory allocation failure during VDI restore operations if memory is limited through cgroupsv2 on Linux. learn.microsoft.com
  11. 11. Fixes an issue in which SSCM fails when it imports certain certificates, including self-signed certificates that are password protected and certificates exported from Azure AKV that are not password protected. learn.microsoft.com
  12. 12. Fixes an issue in which AppDomains in a DOOMED state are not unloaded correctly. learn.microsoft.com
  13. 13. This issue is resolved in the current version of this cumulative update (KB5078297). learn.microsoft.com
  14. 14. Changes the behavior of the program to return error 19544 instead of returning an assert when you create an availability group that has a name that's longer than 64 characters by using cluster_type = NONE or EXTERNAL. learn.microsoft.com
  15. 15. Restricts privileges for dbcc stackdump so that only the sysadmin can invoke the dump file. learn.microsoft.com
  16. 16. Allows using the sys.fn_xe_file_target_read_file() function to read system_health event session data in Azure SQL Managed Instance. learn.microsoft.com
  17. 17. 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, 17 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