CVE-2026-77898CWE-122

CVE-2026-77898

High · published September 8, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
48.4
In the wild
Unconfirmed
What it is

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code over a network.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00608 · 48.4th percentile
Weakness
CWE-122 · Heap-based Buffer Overflow
Published
2026-09-08T22:20Z
Affected products (11)
ProductVersionsFixed in
microsoft/365_appsall versions—
microsoft/365_appsall versions—
microsoft/microsoft_365all 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-2026-77898 · [email protected]
EPSS history
Timeline
  • 10 SEP 03:18Z
    EPSS moved — → 0%
    epss
  • 08 SEP 17:13Z
    Microsoft Office Remote Code Execution Vulnerability
    cvelistv5