Microsoft said on Wednesday that Windows updates released since the October 2026 Patch Tuesday have a bug affecting SQL Server, BleepingComputer reported. Some linked server queries leave their connections to external databases open after they finish. Only queries that use OLE DB providers, the drivers for those links, are affected. Oracle and PostgreSQL are among the known cases. Windows 10, Windows 11 and Windows Server 2012 and later are hit.
Microsoft says an out-of-band fix, meaning one outside the monthly cycle, will come over the next few days. It gave no date. Administrators might see more open connections to external databases, even when no linked server query is running. Closing them by hand or restarting the SQL service can help for a time. But a restart can kill active queries, and the problem may return. The sources do not say which updates carry the bug.
A routine patch, not an attack, can wear down a database tier, and the signs appear on the Oracle or PostgreSQL side. Connections that never close pile up, and performance drops over time. Leaders can ask who owns linked server dependencies, whether anyone watches connection counts, and whether patch tests run cross-database queries.