CVE-2026-64909CWE-122CWE-125CWE-191

CVE-2026-64909

High · published August 11, 2026

CVSS v3.1
7.8
EPSS
0%
Percentile
39.4
In the wild
Unconfirmed
What it is

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

The record
Technical detail
CVSS v3.1
7.8 · HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00466 · 39.4th percentile
Weaknesses
CWE-122 · Heap-based Buffer Overflow; CWE-125 · Out-of-bounds Read; CWE-191 · Integer Underflow (Wrap or Wraparound)
Published
2026-08-11T21:18Z
Affected products (13)
ProductVersionsFixed in
microsoft/365_appsall versions—
microsoft/365_appsall versions—
microsoft/microsoft_365all versions—
microsoft/office_2016all versions—
microsoft/office_2016all versions—
microsoft/office_2019all versions—
microsoft/office_2019all versions—
microsoft/office_2021all versions—
microsoft/office_2021all versions—
microsoft/office_2021all versions—
microsoft/office_2024all versions—
microsoft/office_2024all versions—
microsoft/office_2024all versions—
References (1)
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64909 · [email protected]
EPSS history
Timeline
  • 11 AUG 17:06Z
    Microsoft Office Remote Code Execution Vulnerability
    cvelistv5