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PatchSiren cyber security CVE debrief

CVE-2026-50428 Microsoft CVE debrief

An AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-14T18:17:46.447Z and has not been modified since then. This out-of-bounds read vulnerability in the Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized attacker to disclose information locally. System administrators and security teams should be aware of this vulnerability, particularly those using Windows 11 systems with elevated access or sensitive data.

Vendor
Microsoft
Product
Windows 11 version 26H1
CVSS
HIGH 7.1
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 11 systems, particularly those using the Windows Container Isolation FS Filter Driver (unionfs.sys) or with elevated access or sensitive data, should be aware of this vulnerability and prioritize patching.

Technical summary

CVE-2026-50428 is an out-of-bounds read vulnerability in the Windows Container Isolation FS Filter Driver (unionfs.sys). An authorized attacker could exploit this vulnerability locally to disclose information. The vulnerability has a CVSS score of 7.1 and is classified as HIGH severity. Affected systems include Windows 11, and defenders should focus on patching systems with elevated access or sensitive data.

Defensive priority

High priority should be given to patching affected Windows 11 systems, especially those with elevated access or sensitive data. Defenders should also monitor system logs for potential exploitation attempts and implement compensating controls as needed.

Recommended defensive actions

  • Apply the vendor-provided patch for CVE-2026-50428
  • Conduct a thorough inventory of affected Windows 11 systems
  • Prioritize patching systems with elevated access or sensitive data
  • Monitor system logs for potential exploitation attempts
  • Implement compensating controls, such as additional access restrictions

Evidence notes

The CVE record and NVD detail provide information on the vulnerability. Microsoft has provided a patch and vendor advisory for CVE-2026-50428. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability. Defenders should verify affected systems and apply patches or mitigations as recommended by the vendor. Additional information may be available through vendor advisories or security research reports.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-50428 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-50428

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

  • CVE-2026-50428 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-50428

    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.