PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-67633 Microsoft CVE debrief

An out-of-bounds read vulnerability in Microsoft SQL Server can be exploited by an authorized attacker to deny service over a network. The vulnerability, tracked as CVE-2026-67633, has a CVSS score of 6.5 and is considered medium severity. Microsoft SQL Server versions 2017, 2019, 2022, and 2025 are affected. The CVE record was published on 2026-09-08T18:18:23.753Z and was last modified on 2026-09-16T13:01:52.040Z.

Vendor
Microsoft
Product
Microsoft SQL Server 2017 (CU 31)
CVSS
MEDIUM 6.5
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

Defenders responsible for SQL Server instances, especially those exposed to the internet or used by multiple users, should prioritize patching affected instances.

Why it matters

CVE-2026-67633 is a medium-severity vulnerability in Microsoft SQL Server that can be exploited for denial of service. Defenders should prioritize patching affected instances, verifying inventory, and monitoring for suspicious activity.

  • Denial of service over a network
  • Potential disruption to database operations
  • Need for patching affected SQL Server instances
  • Verification of inventory and monitoring for suspicious activity

Technical summary

The vulnerability is an out-of-bounds read issue in Microsoft SQL Server that can be exploited by an authorized attacker to deny service over a network. Affected versions include SQL Server 2017, 2019, 2022, and 2025. The vulnerability has a CVSS score of 6.5 and is considered medium severity. Defenders should prioritize patching affected SQL Server instances, especially those exposed to the internet or used by multiple users.

Defensive priority

Defenders should prioritize patching affected SQL Server instances, especially those exposed to the internet or used by multiple users.

Recommended defensive actions

  • Patch affected SQL Server instances
  • Verify inventory of SQL Server instances
  • Monitor for suspicious activity

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its CVSS score and affected versions. The vulnerability affects Microsoft SQL Server versions 2017, 2019, 2022, and 2025. Defenders should verify inventory and monitor for suspicious activity. The CVE record was published on 2026-09-08T18:18:23.753Z and was last modified on 2026-09-16T13:01:52.040Z. Evidence is limited, and defenders should exercise caution when verifying affected scope and vendor guidance.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-67633 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-67633

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

  • CVE-2026-67633 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-67633

    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.