The Update BureauKB5075211: Cumulative update for SQL Server 2025, CU branch, February 2026. Six fixes; parallel SESSION_CONTEXT queries can return wrong results
Fixes six SQL Server 2025 issues, including problems with backups, availability groups, and replication. A known issue remains: parallel queries using SESSION_CONTEXT might return incorrect results or produce access violation dump files.
Does it affect you? Applies to: SQL Server 2025 on Windows and Linux. The update package applies to installed SQL Server 2025 components.
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 6 changes
Backup Restore
For: Windows instances
-
StripedVdi tests no longer fail when Sqlvdi.dll is not registered on a running instance.1
Fixes the
StripedVditest failure whenSqlvdi.dllisn't registered on running instances.
High Availability and Disaster Recovery
For: All platforms
-
Availability group replicas receive the same properties when the cluster type is NONE or EXTERNAL.2
Writes availability group properties to the AG configuration for
cluster_type = NONE or EXTERNAL; previously, the properties existed only on the local replica.
Resource Governor
For: All platforms
-
Resource Governor accounting for tempdb space is more accurate when accelerated database recovery is enabled for tempdb.3
Fixes potential inaccuracy in Resource Governor accounting for
tempdbspace when accelerated database recovery is enabled fortempdb.
Storage Management
For: All platforms
-
An assertion and dump files no longer occur around midnight on New Year's Day during an operation that accesses Azure Blob Storage.4
Fixes an assertion and dump file generation around midnight on New Year's Day during an operation that accesses Azure Blob Storage.
Log Management
For: All platforms
-
The availability group secondary replica no longer generates nonyielding scheduler dump files in the stated log-buffer conditions.5
Fixes nonyielding scheduler dump files in
PmmLogAcceptBlockon the AG secondary replica when the persistent log buffer is enabled and the database log cache contains primarily tiny log records.
Replication
For: All platforms
-
The distribution agent uses the availability group listener name instead of the primary replica name in the stated configuration.6
Fixes the distribution agent using the AG primary replica name instead of the AG listener name when the distributor is part of an AG and uses case-sensitive (
_CS) collation.
Known issues
-
Incorrect behavior of SESSION_CONTEXT in parallel plans
Queries using SESSION_CONTEXT might return incorrect results or generate access violation dump files in parallel query plans, particularly if a session is reset for reuse.7
Workaround status No workaround yetMicrosoft 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
- 2026-02-12
- Classification
- Updates
- Type
- Cumulative update
- Servicing branch
- CU
- Restart
- Required
- Replaces
- KB5078298
- Replaced by
- KB5077466
| Version | Build | Channel |
|---|---|---|
| 2025 | 17.0.4015.4 | General availability |
Security
No vulnerabilities are listed for this update.
Downloads (Microsoft Update Catalog)
Updated components
177 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| SQL Server Engine | 24 |
| SQL Server Integration Services | 14 |
| SQL Server Replication | 12 |
| SQL Server Agent | 4 |
| SQL Server Machine Learning Services | 4 |
| SQL Server Full-Text Search | 2 |
| SQL Server PolyBase | 2 |
Sources
Cited passages from Microsoft's official notes (7)
-
1.
Fixes an issue that causes
learn.microsoft.comStripedVditests to fail if theSqlvdi.dllfile isn't registered on running instances. -
2.
For
learn.microsoft.comcluster_type = NONE or EXTERNAL, availability group (AG) properties exist on only the local replica. This update writes the properties to the AG configuration so that all AG replicas receive the same properties. -
3.
Fixes a potential inaccuracy in resource governor accounting for the
learn.microsoft.comtempdbspace if accelerated database recovery is enabled fortempdb. -
4.
Fixes an issue in which an assertion and a dump file are generated around midnight on New Year’s Day during an operation that accesses Azure Blob Storage.
learn.microsoft.com -
5.
Fixes an issue that triggers nonyielding scheduler dump files in
learn.microsoft.comPmmLogAcceptBlockon the availability group (AG) secondary replica. -
6.
Fixes an issue in which the distributor is part of an availability group (AG) and uses case-sensitive (_CS) collation. The distribution agent incorrectly uses the AG primary replica name instead of AG listener name.
learn.microsoft.com -
7.
Queries that use the built-in
learn.microsoft.comSESSION_CONTEXTfunction might return incorrect results or trigger access violation (AV) dump files when run in parallel query plans.
Checked automatically: 8 of 8 checks passed, 7 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