Microsoft released security updates on January 13, 2026, that address a critical elevation of privilege vulnerability in SQL Server. This vulnerability could allow an authenticated attacker to bypass authentication mechanisms and remotely gain elevated system privileges.
See also: Microsoft Patch Tuesday January 2026: Fix 114 vulnerabilities
The vulnerability is tracked with the identifier CVE-2026-20803 and is due to the absence of authentication mechanisms for critical database engine functions.
The issue affects multiple versions of SQL Server, including SQL Server 2022 and the recently released SQL Server 2025.With a CVSS score of 7.2, Microsoft has rated the vulnerability as “Important.” Although its exploitation requires elevated privileges and network access, it could provide attackers with high-impact capabilities, such as memory dumping and access to debug functions, opening the way for further compromise of the system. CVE-2026-20803 is related to the CWE-306, which concerns the lack of authentication for critical functions.
The vulnerability allows already authenticated users with elevated privileges to escalate their access beyond the intended limits, without requiring any user interaction.
See also: Microsoft Patch Tuesday November 2025: Fixes 63 vulnerabilities
An attacker who successfully exploited this vulnerability could gain debug privileges, extract sensitive data from memory, and potentially gain access to encrypted information or extract database credentials stored in memory.
The vulnerability was given an exploitability rating of "Less Likely" when it was first published, indicating that specific conditions are required and that it is not expected to be widely exploited in the near future. However, Microsoft has not reported any active exploitation or attempts at public disclosure.
Microsoft has released security updates for affected versions of SQL Server through the General Distribution Release (GDR) and Cumulative Update (CU). Organizations using SQL Server 2022 should install either CU22 (build 16.0.4230.2) or the RTM GDR (build 16.0.1165.1). SQL Server 2025 users should apply the January GDR (build 17.0.1050.2).
Organizations are urged to prioritize installing updates on systems that are accessible from the internet or handle sensitive data.
See also: Microsoft Patch Tuesday October 2025: 172 vulnerabilities fixed
Finally, Microsoft recommends reviewing the deployment architecture of systems and restricting administrative access to reduce the risk of exploitation during update windows.
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