Microsoft Office Word: Remote code execution via heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Office Word allows an unauthenticated attacker to execute code over a network. Exploitation requires a user to open a crafted document, typically received by email or download, and the code runs with that user's rights. The CVSS base score is 8.8 (High), and the vulnerability is listed as Awaiting Analysis in NVD.
Affected
- Microsoft 365 Apps for Enterprise (32-bit and 64-bit): from 16.0.1, before the fixed build listed at https://aka.ms/OfficeSecurityReleases (build number unknown)
- Microsoft Office 365 for Mac: from 1.0.0 before 16.115.26110837
- Microsoft Office LTSC 2021 (32-bit and 64-bit): from 16.0.1 before 16.0.14334.21048
- Microsoft Office LTSC 2024: from 16.0.0 before 16.0.17932.21140 (unverified, from a third-party source)
- Microsoft Office LTSC for Mac 2021 and 2024: from 16.0.0 or 16.0.1 before 16.115.26110837
Fixed in
- Microsoft Office 365 for Mac: 16.115.26110837 or later
- Microsoft Office LTSC 2021: 16.0.14334.21048 or later
- Microsoft 365 Apps for Enterprise: Unknown, see the Microsoft Office release notes
- Microsoft Office LTSC 2024: 16.0.17932.21140 (unverified, check MSRC)
Workaround
No vendor workaround known. Patching is the only confirmed remediation.
- Interim measure (not from the vendor): block or quarantine Office attachments from untrusted senders.
- Keep Protected View enabled for files from the internet and email.
Exploitation
- Exploited in the wild: no evidence found.
- Public proof of concept: none found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- The CVSS vector indicates exploit code maturity Unproven (E:U).
Our recommendation
- Patch Microsoft Office on all endpoints as soon as possible, with priority for users who handle external documents.
- Check the Microsoft Office release notes and the MSRC advisory for the exact fixed builds.
- Review email gateway rules for Office attachments from unknown senders.
- Monitor NVD and the CISA KEV catalogue for changes.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-112739 msrc.microsoft.com
- CVE.org record CVE-2026-112739 www.cve.org
- Strix AI: CVE-2026-112739 (third-party, unverified) 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, 22:51.
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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