Microsoft Says Windows Updates From October 13 Might Leave SQL Server Linked-Server Connections Open; Fix Promised, Sources Differ on Windows 11 26H2

Overview

Microsoft has confirmed a known issue in which, after Windows updates released October 13, 2026 are installed, connections created by SQL Server linked server queries “might remain open after the queries complete,” according to its Windows Server 2025 release-health page. The page lists the issue as Confirmed and says it was opened at 15:11 PT on 2026-11-11. On the same release-health page, Microsoft promises an out-of-band update “in the next few days.” The Register and BleepingComputer both reported the issue on 2026-11-12. The Register’s account differs from one of Microsoft’s own pages on whether Windows 11, version 26H2 is affected.

What Microsoft’s pages say

The issue affects SQL Server linked server queries that use OLE DB providers to connect to external databases, according to the Windows Server 2025 page, which adds that “Oracle and PostgreSQL connections are among those known to be affected.” The page says connections to external databases can accumulate instead of closing as expected, and that “This can slow or degrade server performance after prolonged run time.” Administrators, it says, “might observe an increasing number of open connections to external databases, even when the associated SQL Server linked server queries are no longer running.”

For interim relief, the same page says that, if idle connections can be identified, they can be closed manually, and that restarting the SQL service can temporarily restore stability. It also warns that “these steps can also interrupt active queries or transactions” and that the problem can resurface after sufficient operation time. A mitigation is available for affected enterprise devices through Microsoft Support for business. The page says Microsoft will update the documentation once the out-of-band update is released.

BleepingComputer reports that the details came in a Windows release health dashboard update on Wednesday (2026-11-11 by the Herald’s calendar reading of that article’s 2026-11-12 date), and that Microsoft says the issue affects both client (Windows 10 and Windows 11) and server (Windows Server 2012 and later) systems. The Register reports the same mitigation route and a fix “within the next few days.”

One issue, several originating updates across the pages

Microsoft publishes the issue separately on the known-issues page of each Windows release, and the eight pages the Herald opened name different originating updates (KB numbers) for different releases. The following mapping is the Herald’s own reading of the eight Microsoft pages it opened on 2026-11-13; the Herald did not open pages for Windows Server 2016, Windows Server 2012 R2 or Windows 11, version 23H2.

• Windows Server 2025: KB5126646.
• Windows Server 2022: KB5126655.
• Windows 10, version 1809 and Windows Server 2019: KB5126651.
• Windows Server 2012: KB5126835.
• Windows 11, version 24H2: KB5127648.
• Windows 11, version 25H2: KB5127648.
• Windows 11, version 26H2: KB5127648.
• Windows 11, version 26H1: KB5127646.

All eight list 2026-10-13 as the originating update’s date. The Register names KB5126646, which is the update the Windows Server 2025 page lists; it does not name the others.

Sources differ on Windows 11, version 26H2

The Register writes: “According to Microsoft, the technical glitch affects every version of Windows except Windows 11 26H2, stretching back to Windows 10 1809 and LTSC 2019, and Windows Server from 2025 back to 2012.” It was published at 12:06 UTC on 2026-11-12, which is 04:06 PT by the Herald’s own conversion.

Microsoft’s Windows 11, version 26H2 page does list the issue, with KB5127648, and shows “Last updated: 2026-11-12, 10:50 PT.” Its affected-platforms list names Windows 11, version 26H2 first among client releases. The Herald counted the platform lists on the eight pages: the 26H2 page lists 13 platforms (seven client, six server), and the other seven pages list 12 (six client, six server) without 26H2. Those seven pages show “Last updated: 2026-11-11, 15:37 PT” for the issue.

None of the cited sources says why the Register’s statement and the 26H2 page differ, or whether the page was edited after the Register article appeared, so the Herald reports both and does not reconcile them. A related wording difference remains unexplained in the cited sources: the Microsoft text says the connections stay open after updates “are installed on server devices,” while the platform lists include Windows 10 and Windows 11 client releases, and BleepingComputer reports both client and server systems as affected.

What is not known

None of the cited sources gives a release date for the out-of-band update. When the Herald opened the eight Microsoft pages on 2026-11-13, each still showed the issue as Confirmed with the same “in the next few days” text. None of the cited sources says how many installations are affected, and Microsoft’s wording on databases is that Oracle and PostgreSQL are “among those” known to be affected, so other OLE DB targets are neither named nor excluded.

BleepingComputer also mentions an earlier SQL Server problem with different symptoms: in September, it reports, Microsoft shared a temporary workaround for SQL Server crashes on some Windows Server 2025 systems that it attributes to recent memory management changes, and which affects SQL Server when the Lock Pages in Memory (LPIM) Windows policy is enabled.