PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-44817 Microsoft CVE debrief

CVE-2026-44817 is a HIGH severity vulnerability in Microsoft Office Excel. An integer underflow (or, wrap/wraparound) vulnerability exists, which could allow an unauthorized attacker to execute code locally. The vulnerability has a CVSS score of 7.8 and was published on [cvePublishedAt](https://www.cve.org/CVERecord?id=CVE-2026-44817).

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
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

Users of Microsoft Office Excel, particularly those using vulnerable versions, should apply patches or mitigations to prevent local code execution.

Technical summary

The vulnerability exists in Microsoft Office Excel due to an integer underflow (or, wrap/wraparound). This could allow an attacker to execute code locally. The Common Vulnerability Scoring System (CVSS) score for this vulnerability is 7.8, indicating a HIGH severity level.

Defensive priority

HIGH

Recommended defensive actions

  • Apply patches or updates provided by Microsoft to vulnerable versions of Microsoft Office Excel.
  • Use secure practices when opening Excel files from untrusted sources.

Evidence notes

The CVE-2026-44817 vulnerability was published on [cvePublishedAt](https://www.cve.org/CVERecord?id=CVE-2026-44817) and modified on [cveModifiedAt](https://nvd.nist.gov/vuln/detail/CVE-2026-44817).

Sources and references

Verified primary and authoritative sources

  • CVE-2026-44817 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-44817

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

  • CVE-2026-44817 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-44817

    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.