Microsoft Office Word: Remote code execution through heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Word allows an unauthorized attacker to execute code over a network. The flaw is rated CVSS 8.8 (High) and affects Microsoft 365 Apps for Enterprise, Office LTSC 2021 and 2024, and Office for Mac. A victim must open a crafted document, so the risk is mainly phishing and malicious files from email or downloads. No login is required for the attacker.
Affected
- Microsoft 365 Apps for Enterprise: from 16.0.1, before the fixed build listed on the Microsoft Office security release page
- Office LTSC 2021 (Windows): from 16.0.1, before 16.0.14334.21048
- Office LTSC 2024 (Windows): from 16.0.0, before 16.0.17932.21140
- Office 365 for Mac and Office LTSC for Mac 2021/2024: from 1.0.0 or 16.0.0 (as listed), before 16.115.26110837
Fixed in
- Office LTSC 2021 (Windows): 16.0.14334.21048 or later
- Office LTSC 2024 (Windows): 16.0.17932.21140 or later (confirm against MSRC)
- Office 365 for Mac and Office LTSC for Mac: 16.115.26110837 or later
- Microsoft 365 Apps for Enterprise: Unknown. See https://aka.ms/OfficeSecurityReleases
Workaround
Unknown. No vendor workaround was found in the sources reviewed. Check the MSRC advisory for any configuration-level mitigation.
Exploitation
- Not confirmed as exploited in the wild for this CVE.
- Microsoft rates exploit code maturity as Unproven (E:U).
- No public proof-of-concept found. This does not confirm that none exists.
- CISA SSVC: exploitation none, automatable no, technical impact total.
Our recommendation
- Identify Word installations on Microsoft 365 Apps, Office LTSC and Office for Mac, and check their build numbers.
- Install the Microsoft Office security update for affected builds, with high priority for staff who handle external documents.
- Until patched, be cautious with unexpected email attachments and downloaded documents.
- Monitor the MSRC advisory and NVD for updates and 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 Response Center advisory CVE-2026-112729 msrc.microsoft.com
- CVE.org CNA record CVE-2026-112729 www.cve.org
- Strix.ai mirror CVE-2026-112729 www.strix.ai
- BleepingComputer: Microsoft November 2026 Patch Tuesday www.bleepingcomputer.com
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, 22:57.
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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