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CVE-2026-49793 Microsoft CVE debrief

A heap-based buffer overflow vulnerability exists in the Windows Resilient File System (ReFS). An authorized attacker can exploit this vulnerability to execute code locally. This vulnerability affects Windows 10, Windows 11, and Windows Server systems. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. System administrators and users should be aware of this vulnerability and apply patches as available.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-22
Advisory published
2026-07-14
Advisory updated
2026-07-22

Who should care

System administrators and users of Windows 10, Windows 11, and Windows Server systems should be aware of this vulnerability and apply patches as available. This vulnerability has a CVSS score of 7.8 and is classified as HIGH severity, indicating a high level of risk. Defenders should prioritize patching and monitoring system logs for suspicious activity.

Technical summary

The vulnerability is a heap-based buffer overflow in the Windows Resilient File System (ReFS). This allows an authorized attacker to execute code locally. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. The Windows Resilient File System (ReFS) is impacted, and defenders should focus on applying patches and monitoring system logs for suspicious activity.

Defensive priority

High

Recommended defensive actions

  • Apply patches as available from Microsoft
  • Ensure that Windows systems are up to date with the latest security updates
  • Monitor system logs for suspicious activity
  • Implement compensating controls such as intrusion detection and prevention systems
  • Review relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record was published on 2026-07-14T17:16:55.050Z and was last modified on 2026-07-20T11:43:55.250Z. The NVD entry is currently Analyzed. This vulnerability affects Windows 10, Windows 11, and Windows Server systems. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. The Windows Resilient File System (ReFS) is impacted, and an authorized attacker can exploit this vulnerability to execute code locally.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-49793 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-49793

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

  • CVE-2026-49793 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-49793

    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.