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PatchSiren cyber security CVE debrief

CVE-2026-81387 Microsoft CVE debrief

Microsoft Office Excel vulnerability CVE-2026-81387 allows unauthorized information disclosure, posing a medium severity risk. Defenders and administrators should assess exposure and prioritize patching to prevent local information disclosure. The vulnerability, detailed in the CVE Program record and NVD vulnerability detail, requires verification of Microsoft Office versions and configurations. Review and apply the Microsoft patch for CVE-2026-81387, and assess local exposure to unauthorized information disclosure.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-17
Advisory published
2026-09-08
Advisory updated
2026-09-17

Who should care

Defenders and administrators of Microsoft Office Excel deployments should assess exposure and prioritize patching to prevent unauthorized information disclosure. Security teams and vulnerability management teams should review the CVE Program record and NVD vulnerability detail for affected scope, severity, and vendor guidance. Operators and platform administrators should verify inventory of Microsoft Office versions,

Why it matters

CVE-2026-81387 allows unauthorized information disclosure in Microsoft Office Excel. Defenders should assess exposure, prioritize patching, and verify inventory of Microsoft Office versions and configurations.

  • Verify patch deployment for Microsoft Office Excel
  • Assess local exposure to unauthorized information disclosure

Technical summary

CVE-2026-81387 is an information disclosure vulnerability in Microsoft Office Excel. An unauthorized attacker can exploit this vulnerability to disclose information locally. The vulnerability details are provided in the official CVE Program record and NVD vulnerability detail. Defenders should assess exposure, prioritize patching, and verify inventory of Microsoft Office versions and configurations.

Defensive priority

Assess exposure, prioritize patching

Recommended defensive actions

  • Review and apply Microsoft patch for CVE-2026-81387
  • Assess exposure of Microsoft Office Excel in your environment
  • Verify inventory of Microsoft Office versions and configurations

Evidence notes

CVE-2026-81387 details an information disclosure vulnerability in Microsoft Office Excel. The CVE Program and NVD provide official records and vulnerability details.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-81387 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-81387

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

  • CVE-2026-81387 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-81387

    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.