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CVE-2026-66814 Microsoft CVE debrief

CVE-2026-66814 debrief based on CVE Program and NVD records. This HIGH severity vulnerability in SQL Server allows an authorized attacker to elevate privileges over a network due to insufficient granularity of access control. SQL Server administrators and security teams should assess exposure, prioritize remediation, and apply patches for affected versions. Monitoring SQL Server logs for potential privilege elevation attempts is also recommended. The CVE record was published on 2026-09-08T18:18:19.880Z and has not been modified since then. Official CVE Program and NVD records confirm this vulnerability, and a vendor advisory and patch are available.

Vendor
Microsoft
Product
Microsoft SQL Server 2017 (CU 31)
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-16
Advisory published
2026-09-08
Advisory updated
2026-09-16

Who should care

SQL Server administrators, security teams, and IT professionals responsible for database security should assess exposure, prioritize remediation, and apply patches for affected SQL Server versions. They should also review and update access controls to ensure least privilege for SQL Server users and monitor SQL Server logs for potential privilege elevation attempts. Additionally, they should verify and apply vendor-p

Why it matters

CVE-2026-66814 is a HIGH severity vulnerability in SQL Server that allows an authorized attacker to elevate privileges over a network. SQL Server administrators and security teams should assess exposure, prioritize remediation, and apply patches for affected versions. Monitoring SQL Server logs for potential privilege elevation attempts is also recommended.

  • Verify and apply patches for affected SQL Server versions to prevent privilege elevation
  • Review and update access controls to ensure least privilege for SQL Server users
  • Monitor SQL Server logs for potential privilege elevation attempts
  • Assess exposure and prioritize remediation for SQL Server deployments

Technical summary

CVE-2026-66814 is a HIGH severity vulnerability in SQL Server, allowing an authorized attacker to elevate privileges over a network due to insufficient granularity of access control in SQL Server. This vulnerability affects SQL Server deployments, and administrators should review and update access controls to ensure least privilege for SQL Server users. Monitoring SQL Server logs for potential privilege elevation attempts is also recommended.

Defensive priority

High priority for SQL Server administrators and security teams

Recommended defensive actions

  • Review and update SQL Server access controls to ensure least privilege
  • Verify and apply vendor patches for affected SQL Server versions
  • Monitor SQL Server logs for potential privilege elevation attempts

Evidence notes

Official CVE Program and NVD records confirm insufficient granularity of access control in SQL Server, allowing an authorized attacker to elevate privileges over a network.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-66814 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-66814

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-66814 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-66814

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.