Microsoft’s SQL Server 2025 Cumulative Update 3 (CU3) is now documented with build 17.0.4025.3 and KB5077896. According to Microsoft, the release contains 15 fixes added after CU2, plus one confirmed known issue affecting SESSION_CONTEXT in parallel query plans.

The update spans a mix of engine, Linux, availability, search, and local development areas. Some changes are straightforward bug fixes, while others are targeted performance or feature updates.

Known issues

Microsoft lists one known issue for CU3:

  • Queries that use SESSION_CONTEXT can return incorrect results or produce access violation dump files when they run in parallel plans. Microsoft attributes this to the way SESSION_CONTEXT interacts with parallel execution threads, especially when a session is reset for reuse.

Improvements and fixes

CU3 includes 15 fixes. The release is spread across several practical areas:

  • Column store and backup/restore scalability: Microsoft says two column store fixes and one backup/restore change improve scalability on large core-count systems. The backup/restore fix aligns the I/O completion structure to a 64-byte cache line size, and the column store fixes address false sharing and cache line invalidation.
  • Storage engine reliability: One fix addresses an assertion error and dump file that may occur when optimized locking and change tracking are both enabled.
  • High availability and disaster recovery: Several fixes cover Contained Availability Groups and Log Shipping behavior, including a configure-only replica that could not reconnect after restart because of a startup failure without the system database, and an issue involving a local monitor server after failover.
  • SQLLocalDB on Windows: Microsoft fixed failures tied to VECTOR functions and crashes associated with REGEX functions.
  • Linux-specific updates: The release corrects sys.dm_os_linux_disk_stats, fixes incorrect log file locations after changing SQL Server edition on Linux, adds symbolic link support in the getattribute API, and introduces configuration changes related to bulk operations.
  • Security and bulk operations on Linux: Microsoft adds support for the Bulkadmin role and ADMINISTER BULK OPERATIONS permissions in Public Preview, allowing secure bulk import without requiring sysadmin access. It also adds a configuration option to add Bulkadmin operations to the allowlist.
  • Search: CU3 introduces a configurable full-text search batch timeout through sp_fulltext_service 'batch_timeout', with a default timeout of 10 minutes when there are no progress updates.
  • SQLPAL on Linux: One fix addresses a crash when a caller requests context that contains only control registers.

Microsoft also notes the component versions updated in this release for SQL Server and Analysis Services.

Official source