CVE-2026-77481: Microsoft SQL Server Remote Code Execution Vulnerability

Overview

Severity

High (CVSS 8.8)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Category

Remote Code Execution

Exploit Status

Not Exploited

Exploitation Likelihood

Unlikely

Patch Tuesday

2026-Sep

Released

2026-09-08

Description

Heap-based buffer overflow in SQL Server allows an authorized attacker to execute code over a network.

FAQ

How could an attacker exploit this vulnerability? An attacker who is authenticated to an affected SQL Server instance and able to create and execute a CLR (SAFE) stored procedure could call a data-handling API with a specially crafted parameter to trigger an out-of-bounds memory write inside the SQL Server process. Successful exploitation could allow the attacker to execute code in the context of the SQL Server service account. Network access and authentication are required; user interaction is not required.

Affected Products (8)

SQL Server

• Microsoft SQL Server 2017 for x64-based Systems (GDR)
• Microsoft SQL Server 2019 for x64-based Systems (GDR)
• Microsoft SQL Server 2017 for x64-based Systems (CU 31)
• Microsoft SQL Server 2022 for x64-based Systems (GDR)
• Microsoft SQL Server 2025 for x64-based Systems (GDR)
• Microsoft SQL Server 2019 for x64-based Systems (CU 32)
• Microsoft SQL Server 2025 for x64-based Systems (CU8)
• Microsoft SQL Server 2022 for x64-based Systems (CU 26)

Security Updates (8)

• 5122775
• 5122773
• 5122774
• 5122771
• 5122770
• 5122772
• 5122769
• 5122768

Acknowledgments

Microsoft Red Team

Revision History

• 2026-09-08: Information published.