Microsoft Office Word: Heap-based buffer overflow allows remote code execution
Summary
A heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network. The attacker needs a user to open a crafted document, for example one received by email or download, and attack complexity is high. Successful exploitation could affect confidentiality, integrity and availability of the affected workstation. NVD analysis was still pending at publication.
Affected
- Microsoft 365 Apps for Enterprise, version 16.0.1 up to the fix (fixed build not stated in the sources)
- Microsoft Office 365 for Mac, 1.0.0 before 16.115.26110837
- Microsoft Office LTSC 2024, 16.0.0 before 16.0.17932.21140
- Microsoft Office LTSC for Mac 2021, 16.0.1 before 16.115.26110837
- Microsoft Office LTSC for Mac 2024, 16.0.0 before 16.115.26110837 (to be verified against the CNA record)
Fixed in
- Microsoft Office LTSC 2024: 16.0.17932.21140 and later
- Microsoft Office 365 for Mac and LTSC for Mac 2021: 16.115.26110837 and later
- Microsoft 365 Apps for Enterprise: Unknown, see Office security releases page
- Office LTSC 2021 for Windows: Unknown, not listed in the retrieved record
Workaround
Unknown. No workaround or mitigation is documented in the sources reviewed.
Exploitation
- Exploitation: none reported in the sources reviewed
- CVSS temporal exploit code maturity: Unproven (E:U)
- CISA SSVC: Exploitation none, Automatable no, Technical impact total
- No public proof of concept or CISA KEV listing found; this is not a confirmed absence
Our recommendation
- Install the Microsoft Office security update on all Windows and Mac clients through the normal update channel
- Prioritise users who open documents from external sources
- Check the MSRC Update Guide for the fixed build of your Microsoft 365 Apps version
- Re-check the MSRC page and CISA KEV in the coming days, as NVD analysis is pending
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE Record CVE-2026-116718 www.cve.org
- Microsoft Security Update Guide msrc.microsoft.com
- Strix.ai CVE-2026-116718 www.strix.ai
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 05:45.
Original description (NVD)
Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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