What is CVE-2026-100208?

CVE-2026-100208 is a high-severity vulnerability in Microsoft 365 Apps For Enterprise, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2026-09-25.

How severe is CVE-2026-100208?

High severity. CVSS v3 base score is 7.5 out of 10.

Integer overflow in Microsoft 365 Apps For Enterprise

CVE-2026-100208

Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.

Vulnerability class: Integer Overflow

Published 2026-09-25 · last modified 2026-09-26.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

CWE-190 — Integer Overflow or Wraparound

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-100208 (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-100208?: CVE-2026-100208 is a high-severity vulnerability in Microsoft 365 Apps For Enterprise, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2026-09-25.
How severe is CVE-2026-100208?: High severity. CVSS v3 base score is 7.5 out of 10.