Junglewise Threat Intelligence

CVE-2026-67643: Microsoft SQL Server heap-based buffer overflow

CVE-2026-67643 · Severity: critical · CVSS 9.8 · Published 2026-09-08

Technologies: Microsoft SQL Server. Vendors: Microsoft.

Executive brief

SQL Server is Microsoft's relational database system used to store and manage critical business data across organizations. A heap-based buffer overflow vulnerability allows an attacker on the network to execute arbitrary code on the affected server without authentication, potentially leading to complete compromise of the database, theft of sensitive data, and disruption of business operations.

Technical details

A heap-based buffer overflow vulnerability exists in Microsoft SQL Server that can be exploited by an unauthenticated attacker over the network. The vulnerability results from improper memory bounds checking in the database engine, allowing an attacker to write beyond allocated heap memory and overwrite adjacent objects. This can be leveraged to achieve remote code execution with the privileges of the SQL Server service. The attack requires network access to the SQL Server port but does not require prior authentication or user interaction. Microsoft has released security updates to address this issue.

Affected products

  • Microsoft SQL Server

Timeline

  • 2026-09-08: disclosed

References

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