What is CVE-2026-44817?

CVE-2026-44817 is a high-severity vulnerability, classified under Access of Resource Using Incompatible Type (Type Confusion). CVSS score: 7.8/10. Published 2026-06-09.

How severe is CVE-2026-44817?

High severity. CVSS v3 base score is 7.8 out of 10.

CVE-2026-44817

CVE-2026-44817

Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Weakness classification (CWE)

CWE-843 — Access of Resource Using Incompatible Type (Type Confusion)

References

secure@microsoft.com

Frequently asked questions

What is CVE-2026-44817?: CVE-2026-44817 is a high-severity vulnerability, classified under Access of Resource Using Incompatible Type (Type Confusion). CVSS score: 7.8/10. Published 2026-06-09.
How severe is CVE-2026-44817?: High severity. CVSS v3 base score is 7.8 out of 10.