Microsoft Office Word: Remote Code Execution via heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Word, part of Microsoft 365 Apps and Office LTSC, allows an unauthorized attacker to execute code over a network. The attack requires user interaction, for example opening a crafted document from an email or download. The details come from third-party mirrors of the CNA record; the MSRC advisory could not be retrieved, so the record is not yet verified.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 onwards (upper bound not confirmed; the CNA record links to a placeholder)
- Office 365 for Mac: 1.0.0 to below 16.115.26110837
- Office LTSC 2021 (Windows): 16.0.1 to below 16.0.14334.21048
- Office LTSC 2024 (Windows): 16.0.0 to below 16.0.17932.21140
- Office LTSC for Mac 2021: 16.0.1 to below 16.115.26110837
- Office LTSC for Mac 2024: 16.0.0 to below 16.115.26110837 (listed in only one of two cached copies; verify)
Fixed in
Unknown. Verify the fixed builds on the MSRC Security Update Guide.
Workaround
Unknown. No vendor-published workaround was found. Until a patch is confirmed, restrict Word documents from untrusted email and downloads, and keep Protected View enabled.
Exploitation
- No exploitation in the wild found at the time of research.
- No public proof of concept found. CISA SSVC: exploitation none, automatable no, technical impact total.
- CISA KEV and GitHub were not checked directly, so this means 'not found', not 'confirmed absent'.
Our recommendation
- Verify the CVE and the affected builds on the MSRC Security Update Guide before making patch decisions, as the record is not yet validated.
- Install the Microsoft Office security updates for all affected versions as soon as they are confirmed, within your normal patch window. Prioritise systems using Microsoft 365 Apps or LTSC Office.
- Until patched, filter or quarantine Word attachments from untrusted sources and keep Protected View enabled.
- Check NVD and CISA KEV once analysis is complete and monitor for signs of exploitation.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide (MSRC) msrc.microsoft.com
- Strix CVE-2026-112718 (third-party mirror of CNA record) www.strix.ai
- Strix CVE-2026-112717 (related sequential ID, record check) www.strix.ai
- Strix CVE-2026-116718 (same description, different score) 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 10 Nov 2026, 22:58.
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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