CVE-2026-55128

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

Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.

Affected (17)

Products: Microsoft: 365 Apps, Microsoft 365, Office 2019, Office 2021, Office 2024, Office Online Server, Sharepoint Server, Word

8 products

Office Online Server

Sharepoint Server

Configuration A

17 vulnerable

Vulnerable Software	Affected Versions
Microsoft 365 Apps	All versions
Microsoft 365 Apps	All versions
Microsoft Microsoft 365	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
Microsoft Office Online Server	Before 16.0.10417.20175
Microsoft Sharepoint Server	Before 16.0.19725.20434
Microsoft Sharepoint Server	Version 2016
Microsoft Sharepoint Server	Version 2019
Microsoft Word	Version 2016
Microsoft Word	Version 2016

Related CWEs

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55128

Source: secure@microsoft.com

Vendor AdvisoryPatch

Timeline

No history available yet.