CVE-2026-78518CWE-125CWE-20

CVE-2026-78518

High · published September 8, 2026

CVSS v3.1
8.8
EPSS
1%
Percentile
58.1
In the wild
Unconfirmed
What it is

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.

The record
Technical detail
CVSS v3.1
8.8 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00859 · 58.1th percentile
Weaknesses
CWE-125 · Out-of-bounds Read; CWE-20 · Improper Input Validation
Published
2026-09-08T22:20Z
Affected products (15)
ProductVersionsFixed in
microsoft/365_appsall versions—
microsoft/365_appsall versions—
microsoft/excelall versions—
microsoft/excelall 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-2026-78518 · [email protected]
EPSS history
Timeline
  • 10 SEP 03:18Z
    EPSS moved — → 1%
    epss
  • 08 SEP 17:13Z
    Microsoft Office Excel Remote Code Execution Vulnerability
    cvelistv5