PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-44818 Microsoft CVE debrief

CVE-2026-44818 is a HIGH-severity vulnerability in Microsoft Office Excel, with a CVSS score of 7. The vulnerability is caused by an integer underflow (wrap or wraparound) and allows an unauthorized attacker to execute code locally. The vulnerability was published on 2026-06-09T17:17:18.040Z and modified on 2026-06-11T18:38:18.510Z.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
HIGH 7
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 is caused by an integer underflow (wrap or wraparound) in Microsoft Office Excel. This allows an unauthorized attacker to execute code locally. The CVSS vector is CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.

Defensive priority

HIGH

Recommended defensive actions

  • Apply patches or updates from Microsoft to fix the vulnerability.
  • Use secure configurations and best practices for Microsoft Office Excel.
  • Monitor for suspicious activity and implement incident response plans.

Evidence notes

The vulnerability is tracked as CWE-362 and has been analyzed by the National Vulnerability Database (NVD).

Sources and references

Verified primary and authoritative sources

  • CVE-2026-44818 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-44818

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

  • CVE-2026-44818 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-44818

    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.