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CVE-2026-42836 Microsoft CVE debrief

CVE-2026-42836 is a HIGH-severity vulnerability in Microsoft Windows, with a CVSS score of 7. The vulnerability is caused by a concurrent execution using shared resource with improper synchronization, also known as a race condition, in the Function Discovery Service (fdwsd.dll). This allows an authorized attacker to elevate privileges locally.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-11
Advisory published
2026-06-09
Advisory updated
2026-06-11

Who should care

Administrators and users of Microsoft Windows systems, particularly those with local access, should be aware of this vulnerability.

Technical summary

The vulnerability exists in the Function Discovery Service (fdwsd.dll) and can be exploited by an authorized attacker to elevate privileges locally. The CVSS vector is CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

Defensive priority

High

Recommended defensive actions

  • Apply patches from Microsoft as soon as possible.
  • Review and apply mitigations from the vendor advisory (see resourceLinkAnnotations/ref-4).

Evidence notes

The CVE record (see resourceLinkAnnotations/cve-org) and NVD detail (see resourceLinkAnnotations/nvd) provide additional information about the vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-42836 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-42836

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

  • CVE-2026-42836 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-42836

    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.