CVE-2026-55035: Microsoft Office out-of-bounds read information disclosure

CVE-2026-55035 · Severity: medium · CVSS 5.5 · Published 2026-07-14

A security vulnerability in Microsoft Office could allow an attacker to access sensitive information on a user's computer. To exploit this, an attacker would typically need to trick a user into opening a specially crafted file. This could lead to the unauthorized disclosure of private data stored in the system's memory.

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

Quick answers

Is CVE-2026-55035 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-55035 being exploited in the wild.
How severe is CVE-2026-55035?
Medium severity, with a CVSS score of 5.5, published 14 July 2026.
Which products and versions are affected?
Microsoft 365 Apps for Enterprise All versions; Microsoft Office 2016 < 16.0.5561.1000; Microsoft Office 2019 All versions; Microsoft Office 365 for Mac < 16.111.26071215; and 3 more.
Is there a fix for CVE-2026-55035?
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-2026-55035 attacked?
It is attacked with local access, in a network appliance.
Am I affected by CVE-2026-55035?
Check whether you run Microsoft 365 Apps for Enterprise, Microsoft Office 2016, Microsoft Office 2019 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

An out-of-bounds read vulnerability (CWE-125) exists in multiple versions of Microsoft Office and SharePoint Server. The flaw is triggered when the application improperly handles memory while parsing a specially crafted file. An attacker can exploit this by convincing a user to open a malicious document, allowing the attacker to read sensitive information from the process memory. This is a local attack vector requiring user interaction, with a CVSS base score of 5.5. Microsoft has released security updates to address this issue across affected products including Office 2016, 2019, LTSC, and Microsoft 365 Apps.

Affected products

  • Microsoft Office 2016 < 16.0.5561.1000
  • Microsoft Office 2019 All versions
  • Microsoft Office LTSC 2021 All versions
  • Microsoft Office LTSC 2024 All versions
  • Microsoft 365 Apps for Enterprise All versions
  • Microsoft Office 365 for Mac < 16.111.26071215
  • Microsoft SharePoint Enterprise Server 2016 < 16.0.5561.1001

Timeline

  • 2026-07-14: disclosed
  • 2026-07-14: advisory

References

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