CVE-2026-55130: Microsoft Office Word heap buffer overflow

CVE-2026-55130 · Severity: high · CVSS 7.8 · Published 2026-07-14

A vulnerability in Microsoft Office Word could allow an attacker to execute malicious code on a user's computer. This typically occurs if a user is tricked into opening a specially crafted document. Successful exploitation could lead to a full compromise of the user's data and system access.

Technologies: Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, Microsoft SharePoint Server Subscription Edition, Microsoft Word 2016. Vendors: Microsoft.

Quick answers

Is CVE-2026-55130 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-55130 being exploited in the wild.
How severe is CVE-2026-55130?
High severity, with a CVSS score of 7.8, published 14 July 2026.
Which products and versions are affected?
Microsoft 365 Apps for Enterprise >= 16.0.1; Microsoft Office 2019 >= 19.0.0; Microsoft Office LTSC 2021 >= 16.0.1; Microsoft Office LTSC 2024 >= 16.0.0; and 4 more.
Is there a fix for CVE-2026-55130?
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-2026-55130 attacked?
It is attacked with local access, in a network appliance.
Am I affected by CVE-2026-55130?
Check whether you run Microsoft 365 Apps for Enterprise, Microsoft Office 2019, Microsoft Office LTSC 2021 or one of the others listed 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 heap-based buffer overflow (CWE-122) exists in Microsoft Office Word and related SharePoint server components. The vulnerability is triggered when the application fails to properly validate input while processing a document, leading to memory corruption. An attacker can exploit this by convincing a user to open a malicious file, resulting in arbitrary code execution in the context of the current user. The attack vector is local with a requirement for user interaction (UI:R). Microsoft has released security updates to address this issue across affected Office and SharePoint versions.

Affected products

  • Microsoft Microsoft 365 Apps for Enterprise >= 16.0.1
  • Microsoft Microsoft Office 2019 >= 19.0.0
  • Microsoft Microsoft Office LTSC 2021 >= 16.0.1
  • Microsoft Microsoft Office LTSC 2024 >= 16.0.0
  • Microsoft Microsoft SharePoint Enterprise Server 2016 < 16.0.5561.1001
  • Microsoft Microsoft SharePoint Server 2019 < 16.0.10417.20175
  • Microsoft Microsoft SharePoint Server Subscription Edition < 16.0.19725.20434
  • Microsoft Microsoft Word 2016 < 16.0.5561.1000

Timeline

  • 2026-07-14: disclosed: Initial publication of CVE-2026-55130 by Microsoft.

References

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