CVE-2026-55140

Published: Jul 14, 2026Modified: Jul 16, 2026

7.8

Vector

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

Exploitability: 1.8 / Impact: 5.9

Source: secure@microsoft.com (Secondary)

Description

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

Affected (13)

Products: Microsoft: 365 Apps, Microsoft 365, Office 2016, Office 2019, Office 2021, Office 2024

6 products

Configuration A

13 vulnerable

Vulnerable Software	Affected Versions
Microsoft 365 Apps	All versions
Microsoft 365 Apps	All versions
Microsoft Microsoft 365	All versions
Microsoft Office 2016	All versions
Microsoft Office 2016	All versions
Microsoft Office 2019	All versions
Microsoft Office 2019	All versions
Microsoft Office 2021	All versions
Microsoft Office 2021	All versions
Microsoft Office 2021	All versions
Microsoft Office 2024	All versions
Microsoft Office 2024	All versions
Microsoft Office 2024	All versions

Related CWEs

Heap-based Buffer Overflow

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55140

Source: secure@microsoft.com

PatchVendor Advisory

Timeline

No history available yet.