# CVE-2026-55128: Microsoft Office Word use after free code execution

Source: https://junglewise.ai/threats/cve-2026-55128-microsoft-office-word-use-after-free-code-execution  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-14. Updated: 2026-07-14  
License: CC BY 4.0 with a link back

CVE-2026-55128 · Severity: high · CVSS 7.8 · Published 2026-07-14

Microsoft Office Word, a widely used word processing application, contains a security flaw that could allow an attacker to take control of a user's computer. To exploit this, an attacker would typically need to trick a user into opening a specially crafted malicious document. Successful exploitation could lead to unauthorized access to sensitive data, installation of malicious software, or a complete system compromise.

Technologies: [Microsoft SharePoint Server](https://junglewise.ai/threats/technologies/sharepoint-server), [Microsoft Word](https://junglewise.ai/threats/technologies/word). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-55128 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55128 being exploited in the wild.

**How severe is CVE-2026-55128?** High severity, with a CVSS score of 7.8, published 14 July 2026.

**Which products and versions are affected?** Microsoft Word Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, SharePoint Server.

**Is there a fix for CVE-2026-55128?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-55128 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-55128?** Check whether you run Microsoft SharePoint Server or Microsoft Word at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A use-after-free (UAF) vulnerability exists in Microsoft Office Word (CWE-416). The flaw is triggered when the application improperly handles objects in memory, allowing an attacker to execute arbitrary code in the context of the current user. The attack vector is local, but it requires user interaction (UI:R), such as opening a malicious document. Affected products include Microsoft 365 Apps, Office 2019, Office LTSC 2021 and 2024, and several versions of SharePoint Server. Microsoft has released security updates to address this issue.

## Affected products

- Microsoft Office Word Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, SharePoint Server

## Timeline

- 2026-07-14: disclosed
- 2026-07-14: advisory: Microsoft released security updates.

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55128](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55128)

## Related threats

- [Microsoft Word use-after-free remote code execution](https://junglewise.ai/threats/cve-2026-112735-use-after-free-in-microsoft-office-word-allows-an-unauthorized)
- [Microsoft Word heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-112724-heap-based-buffer-overflow-in-microsoft-office-word-allows-an)
- [Microsoft Word heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-112716-heap-based-buffer-overflow-in-microsoft-office-word-allows-an)
- [Microsoft Word heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-111306-heap-based-buffer-overflow-in-microsoft-office-word-allows-an)
- [Microsoft Office Word heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-110056-heap-based-buffer-overflow-in-microsoft-office-word-allows-an)