Stack-based buffer overflow in SQL Server allows an authorized attacker to elevate privileges over a network.
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires an attacker to have a deep understanding of the system and the ability to manipulate its components to trigger a specific condition. Successful exploitation is not guaranteed and depends on a combination of factors that may include the environment, system configuration, and the presence of additional security measures. What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges. I am running SQL Server on my system. What action do I need to take? Update your relevant version of SQL Server using the applicable October 2026 security update listed below. There are GDR and/or CU (Cumulative Update) updates offered for my version of SQL Server. How do I know which update to use? First, determine your SQL Server version number. For more information, see Microsoft Knowledge Base Article 321185 - How to determine the version, edition, and update level of SQL Server and its components. Second, locate the range containing your current version number in the following table. The corresponding update is the one you need to install. Note: If your version is not represented in the table, review the applicable update's prerequisites and the support status of your SQL Server release before choosing an update. Absence from this table alone does not establish that a version is unsupported. Update Number Title Version Apply if current product version is… This security update also includes servicing releases up through… 5126967 SQL Server 2025 CU9+GDR (October GDR 2026) 17.0.5015.4 17.0.4006.2 - 17.0.5005.3 KB5122048 - SQL2025 RTM CU9 5128492 SQL Server 2025 RTM+GDR (October GDR 2026) 17.0.1145.4 17.0.1000.7 - 17.0.1135.8 KB5122770 - Previous SQL2025 RTM GDR 5126934 SQL Server 2022 CU27+GDR1
<a href="https://twitter.com/arudd1ck">Andrew Ruddick</a> with Microsoft Red Team