In brief: On 11 November 2026 Microsoft confirmed a known issue: after Windows updates released on 13 October 2026 (KB5126646) and later are installed on server devices, connections created by SQL Server linked server queries might remain open after the queries complete. The connections accumulate and can slow server performance over time. Windows Server 2012 through 2025 are affected, and Microsoft says an out-of-band update will be released “in the next few days”.
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According to the official Windows Server 2025 release health page on Microsoft Learn, the issue was opened on 11 November 2026 with the status “Confirmed”. Microsoft explains that connections created by SQL Server linked server queries might stay open after the queries finish. As additional queries are performed, connections to external databases can accumulate instead of closing as expected, which can slow or degrade server performance after prolonged run time.
The issue affects linked server queries that use OLE DB providers to connect to external databases. Microsoft names Oracle and PostgreSQL connections among those known to be affected. Administrators might see a growing number of open connections to external databases even when the related linked server queries are no longer running.
Affected versions
- Server: Windows Server 2025, Windows Server 2022, Windows Server version 1809, Windows Server 2016, Windows Server 2012 R2 and Windows Server 2012.
- Client: Windows 11 versions 26H1, 25H2, 24H2 and 23H2; Windows 10 version 1809; Windows 10 Enterprise LTSC 2019.
KB5126646 is the 13 October update for Windows Server 2025 (OS Build 26100.33650); the other versions are affected by their updates released on the same date and later.
Temporary workarounds until the fix
- If idle connections can be identified, close them manually to temporarily relieve server load.
- Restart the SQL Server service to temporarily restore stability.
- Microsoft warns that both steps can interrupt active queries or transactions, and the problem can return after enough operating time.
- A mitigation is available for affected enterprise devices through Microsoft Support for business.
The Register, covering the issue on 12 November, noted that restarting a database server to deal with connection leakage is “less than ideal” and that the lasting fix is the expected out-of-band update.
What does this mean for your system?
RivDesktop by Riv-ERP runs on .NET and Windows with a SQL Server database on the company’s own server, so your IT administrator should follow this issue. Practical steps:
- Check first: does your SQL Server use linked servers? Look in SQL Server Management Studio (Server Objects → Linked Servers) or run
SELECT name, provider FROM sys.servers WHERE is_linked = 1;. If there are no linked servers, the issue as Microsoft describes it does not apply to your server. - Monitor connection counts to external databases if you have integrations that go through a linked server, especially to Oracle or PostgreSQL.
- If you need to restart the SQL Server service, do it outside working hours and after a backup, so invoices or journal entries being saved are not interrupted.
- Install the out-of-band update once released and tested, as part of the monthly patch routine we covered in SQL Server October 2026 security updates.
Riv-ERP Cloud runs on Oracle APEX and Oracle Database on Oracle Cloud, not on a customer-side SQL Server. If you are planning a server upgrade, see our SQL Server 2025 upgrade guide, or request a quote and talk to us about reviewing your server environment.
Note: this news item is general information based on Microsoft’s notice at the time of publishing; Microsoft may update the notice when the fix is released.
Sources
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