Junglewise Threat Intelligence

CVE-2026-66814: Microsoft SQL Server privilege escalation via access control

CVE-2026-66814 · Severity: high · CVSS 8.8 · Published 2026-09-08

Technologies: Microsoft SQL Server. Vendors: Microsoft.

Executive brief

SQL Server is a widely-used database platform that many organizations rely on to store and manage business-critical data. This vulnerability allows an attacker who already has authorized access to SQL Server to bypass security controls and gain higher-level privileges, potentially granting access to sensitive data or allowing them to modify database contents without proper authorization.

Technical details

The vulnerability stems from insufficient granularity in SQL Server's access control implementation, allowing privilege escalation over the network. An authenticated attacker—one who already possesses valid credentials—can exploit this to escalate their privileges beyond what they were originally authorized to have. The attack vector is network-based, requiring an active connection to SQL Server. This is a post-authentication privilege escalation vulnerability; while an attacker must already be authenticated to exploit it, the impact is severe as it undermines the principle of least privilege that access control systems are designed to enforce.

Affected products

  • Microsoft SQL Server

Timeline

  • 2026-09-08: disclosed

References

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