CVE-2026-44818

HIGH

Published Jun 9, 2026 Modified Jun 11, 2026 CWE-362

Description

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

CVSS v3.1 Score

7.0

HIGH

CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0026

Probability of exploitation

0.18%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-362 CWE-362

Affected Products

Vendor	Product	Versions
microsoft	365_apps	All
microsoft	365_apps	All
microsoft	excel	All
microsoft	excel	All
microsoft	microsoft_365	All
microsoft	office_2019	All
microsoft	office_2019	All
microsoft	office_2021	All
microsoft	office_2021	All
microsoft	office_2021	All
microsoft	office_2024	All
microsoft	office_2024	All
microsoft	office_2024	All
microsoft	office_online_server	All

References

Advisories & Patches

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44818

Frequently Asked Questions

What is CVE-2026-44818? +

Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally. It has a CVSS v3.1 base score of 7.0 (HIGH).

How severe is CVE-2026-44818? +

CVE-2026-44818 has a CVSS v3.1 score of 7.0 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-44818? +

CVE-2026-44818 affects products from microsoft, specifically: 365_apps, excel, microsoft_365, office_2019, office_2021, office_2024, office_online_server. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-44818? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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