CVE-2026-55128 Details
Description
Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.
A use-after-free vulnerability has been identified in Microsoft Office Word. This flaw allows an unauthorized attacker to execute code locally. The vulnerability arises when an object is accessed after it has been freed, potentially leading to memory corruption and arbitrary code execution.
Users can download the security update for Microsoft Word 2016 (32-bit and 64-bit editions) from the Microsoft Update Catalog. For Microsoft Office LTSC 2021 (32-bit and 64-bit editions), the security update is also available through the Microsoft Update Catalog. Microsoft Office 365 for Mac users can download the security update from the Microsoft 365 for Mac release notes page. SharePoint Server 2019 and SharePoint Enterprise Server 2016 users can download the security update from the Microsoft Download Center.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 15, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55128 | [email protected] | Vendor AdvisoryPatch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-416 | Use After Free | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| microsoft 365 apps | All versions |
CPE
Remediation
| |
| microsoft microsoft 365 | All versions |
CPE
Remediation
| |
| microsoft office 2019 | All versions |
CPE
Remediation
| |
| microsoft office 2021 | All versions |
CPE
Remediation
| |
| microsoft office 2024 | All versions |
CPE
Remediation
| |
| microsoft office online server | < 16.0.10417.20175 |
CPE
Remediation
| |
| microsoft sharepoint server | < 16.0.19725.20434 2016 2019 |
CPE
Remediation
| |
| microsoft word | 2016 |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 16, 2026 | Initial Analysis | [email protected] |
| Jul 15, 2026 | CVE Modified | CISA-ADP |
| Jul 15, 2026 | CVE Modified | CISA-ADP |
| Jul 14, 2026 | New CVE Received | [email protected] |