Microsoft has released SQL Server 2025 Cumulative Update 8 (CU8), also known as KB5104822, for build 17.0.4075.5. According to Microsoft, this update contains 11 fixes that were released after SQL Server 2025 CU7 and updates both the SQL Server engine and Analysis Services components.
The release is especially relevant if you use JSON features, linked servers, maintenance plans, or backup and restore workflows, since several of the fixes target those areas directly.
Known issues
Microsoft documents three known issues with this update package:
- SESSION_CONTEXT in parallel plans can return incorrect results or produce access violation dump files when queries run in parallel query plans, especially if the session is reset for reuse.
- Linked server queries using MSDASQL with a provider string can fail with Msg 7416 because of stricter connection validation for certain configurations.
- sys.dm_exec_requests during recovery can raise an access violation and generate a dump file if queried while a database is still recovering, such as during RESTORE, startup recovery, or before an availability group replica finishes coming online.
For the recovery-related issue, Microsoft says it is aware of the problem and investigating a fix. It also lists mitigations including trace flag 4696, avoiding queries against recovering databases, or uninstalling the update. Microsoft also notes that removal of a known issue from the source does not prove resolution unless the source explicitly says so.
Improvements and fixes
Microsoft lists 11 fixes in CU8. The changes are spread across several areas:
- Backup and restore: on Windows, restoring a database with VSS and WITH MOVE could take a long time or time out when the server had hundreds of databases.
- Maintenance plans: an index rebuild maintenance plan could stop responding because of a long-running query.
- Setup and deployment: SQL Server Setup now recommends the correct max server memory value for Standard and Standard Developer editions.
- Linux-specific updates: one fix addresses a collation-change issue during initial setup that could block mssql-conf on systems with a high CPU count; another adds encryption support for communication between the PolyBase external service and gRPC clients on Linux.
- Replication: sp_adddistributor gains a new optional parameter, @multi_subnet_failover.
- Programmability and JSON: several fixes address edge cases in OPENJSON, DBCC CHECKTABLE, and JSON_MODIFY, including unexpected rows from special pattern-matching characters in JSON paths, assertion and dump file conditions with native json data, and errors that appear when native json arrays reach or exceed 65,535 and 65,536 elements.
Other representative fixes include bug references 4929794, 5189710, 5197076, 5379749, 5400887, 5414824, 5425855, 5434644, 5446188, 5446201, and 5446209.
If you rely on JSON-heavy workloads, linked-server access, or maintenance automation, CU8 is worth reviewing closely because it concentrates multiple engine fixes in those paths.