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PatchSiren cyber security CVE debrief

CVE-2026-42837 Microsoft CVE debrief

CVE-2026-42837 is a HIGH severity vulnerability in the Windows Projected File System Filter Driver. A buffer over-read issue exists that allows an authorized attacker to elevate privileges locally. The vulnerability has a CVSS score of 7.8.

Vendor
Microsoft
Product
Windows Projected File System Filter Driver
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-07-09
Advisory published
2026-06-09
Advisory updated
2026-07-09

Who should care

Administrators and users of affected Microsoft Windows systems should prioritize patching this vulnerability to prevent local privilege escalation attacks.

Technical summary

The vulnerability exists in the Windows Projected File System Filter Driver and is caused by a buffer over-read issue. This allows an authorized attacker to elevate privileges locally.

Defensive priority

HIGH

Recommended defensive actions

  • Apply patches from Microsoft as soon as possible.
  • Review and update system configurations to ensure proper protections are in place.
  • Monitor systems for unusual activity that could indicate exploitation attempts.

Evidence notes

The CVE-2026-42837 vulnerability was published on 2026-06-09 and modified on 2026-06-11. It affects various versions of Microsoft Windows.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-42837 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-42837

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

  • CVE-2026-42837 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-42837

    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.