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PatchSiren cyber security CVE debrief

CVE-2026-44821 Microsoft CVE debrief

CVE-2026-44821 is an out-of-bounds read vulnerability in Microsoft Office that allows an unauthorized attacker to disclose information locally. The vulnerability has a CVSS score of 5.5 and a severity of MEDIUM. It was published on 2026-06-09T17:17:18.443Z and modified on 2026-06-11T18:40:00.750Z.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-19
Advisory published
2026-06-09
Advisory updated
2026-06-19

Who should care

Users of Microsoft Office, particularly those using Microsoft 365 Apps, Office 2016, Office 2019, Office 2021, and Office 2024, as well as SharePoint Server, should be aware of this vulnerability.

Technical summary

The vulnerability is caused by an out-of-bounds read in Microsoft Office, which allows an unauthorized attacker to disclose information locally. The CVSS vector is CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.

Defensive priority

MEDIUM

Recommended defensive actions

  • Apply patches or updates provided by Microsoft to fix the vulnerability.
  • Use secure practices when handling sensitive information.
  • Monitor system logs for potential exploitation attempts.

Evidence notes

The vulnerability is described in the CVE record [cve-org]. Details can be found in the NVD detail page [nvd]. Microsoft has provided a vendor advisory [ref-4].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-44821 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-44821

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

  • CVE-2026-44821 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-44821

    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.