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CVE-2026-71345 Microsoft CVE debrief

An out-of-bounds write vulnerability in Windows Spaceport.sys allows an authorized attacker to execute code locally. This issue affects multiple Windows versions, including Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 Version 26H1, Windows Server 2012, Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, Windows Server 2022, and Windows Server 2025. The vulnerability has been addressed by Microsoft. Defenders should assess exposure and apply the patch to prevent local code execution, which can lead to unauthorized access and have

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-22
Advisory published
2026-09-08
Advisory updated
2026-09-22

Who should care

Defenders responsible for Windows systems, especially those with authorized access, should assess exposure and apply the patch. This vulnerability can lead to local code execution, which can have significant consequences if exploited.

Why it matters

CVE-2026-71345 is a High-severity vulnerability in Windows Spaceport.sys that allows authorized attackers to execute code locally. Defenders should assess exposure, apply the patch, and monitor for suspicious activity.

  • Local code execution can lead to unauthorized access and control of affected systems
  • Authorized attackers can exploit this vulnerability to elevate privileges
  • Successful exploitation can result in lateral movement within the network
  • Patching is required to prevent exploitation

Technical summary

The vulnerability is an out-of-bounds write issue in Windows Spaceport.sys, which can allow an authorized attacker to execute code locally. The CVSS score for this vulnerability is 7.8, indicating a High severity level. Affected versions include Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 Version 26H1, Windows Server 2012, Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, Windows Server 2022, and Windows Server 2025.

Defensive priority

High

Recommended defensive actions

  • Assess exposure for Windows systems, especially those with authorized access
  • Verify and apply Microsoft's patch for CVE-2026-71345
  • Monitor for suspicious activity related to Spaceport.sys
  • Review system logs for potential exploitation attempts

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, including its CVSS score of 7.8 and affected Windows versions. Microsoft has released a patch for this issue.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-71345 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-71345

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

  • CVE-2026-71345 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-71345

    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.