Quick answers
- Is CVE-2026-55055 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-55055 being exploited in the wild.
- How severe is CVE-2026-55055?
- 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, Office for Mac, SharePoint Server.
- Is there a fix for CVE-2026-55055?
- 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-2026-55055 attacked?
- It is attacked with local access, in a network appliance.
- Am I affected by CVE-2026-55055?
- 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 stack-based buffer overflow (CWE-121) exists in Microsoft Office Word. The vulnerability is triggered when the application fails to properly validate input while parsing a document, allowing an attacker to overwrite memory on the stack. While the attack vector is classified as local, it typically requires user interaction (UI:R), such as opening a malicious Word document received via email or downloaded from the web. Successful exploitation allows for arbitrary code execution in the context of the current user. Microsoft has released security updates to address this issue across various versions of Office and SharePoint Server.
Affected products
- Microsoft Office Word Microsoft 365 Apps, Office 2019, Office LTSC 2021/2024, Office for Mac, SharePoint Server
Timeline
- 2026-07-14: disclosed
- 2026-07-14: advisory