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PatchSiren cyber security CVE debrief

CVE-2026-50381 Microsoft CVE debrief

CVE-2026-50381 is a medium-severity vulnerability in the Composite Image File System Driver that allows an authorized local attacker to disclose information due to a type confusion issue. The vulnerability has a CVSS score of 5.5 and is classified as CWE-843. Affected systems include Windows 10, Windows 11, and Windows Server. The vulnerability's impact is primarily local, requiring an authorized attacker. The source confidence is limited to CVE and NVD details.

Vendor
Microsoft
Product
Windows 10 Version 21H2
CVSS
MEDIUM 5.5
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 security teams responsible for Windows 10, Windows 11, and Windows Server systems should be aware of this vulnerability and take steps to mitigate it. They should review system configurations, prioritize patching based on risk, and implement compensating controls.

Technical summary

The Composite Image File System Driver is vulnerable to a type confusion issue, which allows an authorized local attacker to disclose information. The vulnerability has a CVSS score of 5.5 and is classified as CWE-843. The technical impact is information disclosure, and the attack vector is local. There are no known exploits or additional technical details available.

Defensive priority

Medium priority due to the local attack vector and potential for information disclosure. Defenders should focus on patching, monitoring, and verifying system configurations.

Recommended defensive actions

  • Apply the vendor-provided patch for CVE-2026-50381
  • Conduct a thorough inventory of affected systems and prioritize patching based on risk
  • Implement compensating controls such as monitoring and exception tracking for suspicious activity
  • Verify the effectiveness of the patch and compensating controls through testing and validation
  • Review relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record was published on 2026-07-14T17:17:01.027Z and last modified on 2026-07-16T13:45:02.280Z. The NVD entry is currently Analyzed. The Composite Image File System Driver vulnerability allows an authorized local attacker to disclose information due to a type confusion issue. Evidence is limited to CVE and NVD details. Defenders should verify system configurations, review for affected deployments, and monitor for suspicious activity.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-50381 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-50381

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

  • CVE-2026-50381 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-50381

    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.