CVE-2026-83951 Microsoft CVE debrief

Who should care

Defenders responsible for Microsoft Office deployments, particularly those using affected versions of Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, and Microsoft Word 2016.

Why it matters

The CVE-2026-83951 vulnerability in Microsoft Office Word allows local information disclosure. Defenders should prioritize patching affected versions, verify vulnerability status, and assess exposure.

• Potential information disclosure in local attacks
• Verification of vulnerability status for affected Microsoft Office versions
• Patching priority for deployments using vulnerable Microsoft Office versions
• Inventory and assessment of exposure for affected Microsoft Office deployments

Technical summary

The vulnerability is caused by a buffer over-read in Microsoft Office Word, allowing an unauthorized attacker to disclose information locally. The CVSS score is 5.5, with a medium severity. Affected products include Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, and Microsoft Word 2016. Defenders should apply patches, verify vulnerability status, and assess exposure.

Defensive priority

Medium-priority patching and verification recommended for affected Microsoft Office deployments.

Recommended defensive actions

• Apply patches for affected Microsoft Office versions
• Verify vulnerability status for Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, and Microsoft Word 2016
• Inventory and assess exposure of affected Microsoft Office deployments

Evidence notes

The CVE record and source item provide details on the vulnerability, but limited information is available on exploitation or impact. The CVE Program record and NIST NVD detail page offer official guidance. Vendor advisory and patch information are also available. Defenders should verify affected scope, severity, and vendor guidance.

Sources and 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.