Microsoft Office Word: Heap-based buffer overflow enables code execution
Summary
A heap-based buffer overflow in Microsoft Word, the document editor in Microsoft Office, allows an unauthorized attacker to execute code over a network. The attack requires user interaction, typically opening a crafted document received by email or download, and no privileges. CISA SSVC rates exploitation as none, and no public proof of concept or in-the-wild exploitation was found in the sources reviewed.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 to before the build listed at aka.ms/OfficeSecurityReleases (exact build unknown)
- Office 365 for Mac: before 16.114.26101123
- Office LTSC 2021: 16.0.1 to before 16.0.14334.20974
- Office LTSC 2024: 16.0.0 to before 16.0.17932.21056
- Office LTSC for Mac 2021: 16.0.1 to before 16.114.26101123
- Office LTSC for Mac 2024: 16.0.0 to before 16.114.26101123
Fixed in
- Office LTSC 2021: 16.0.14334.20974 or later (from aggregator data, not yet confirmed on MSRC)
- Office LTSC 2024: 16.0.17932.21056 or later (from aggregator data, not yet confirmed on MSRC)
- Office for Mac and LTSC for Mac: 16.114.26101123 or later (from aggregator data, not yet confirmed on MSRC)
- Microsoft 365 Apps for Enterprise: fixed build unknown, check the Microsoft 365 release notes linked from aka.ms/OfficeSecurityReleases
Workaround
Unknown. No workaround is documented in the sources reviewed. Check the MSRC advisory for any mitigation.
Exploitation
- CISA SSVC: exploitation none, automatable no
- Not listed in CISA KEV
- EPSS data conflicts between sources (0.00618 in one record, unknown in another)
- No public proof of concept or in-the-wild exploitation found; this does not prove absence. Check the MSRC Exploitation Detected field.
Our recommendation
- Install the latest Microsoft Office security update on all Office installations, prioritising Office LTSC and perpetual-licence installs that do not update automatically
- Confirm the fixed build against the MSRC advisory before closing the ticket
- Check Microsoft 365 tenants to confirm automatic updates were deployed
- Restrict or scan email attachments and downloads for Office documents, and train users not to open unexpected documents
- Monitor for unusual Word process activity and review the MSRC advisory for any mitigations
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-108432 msrc.microsoft.com
- OpenCVE: CVE-2026-108432 app.opencve.io
- Strix AI: CVE-2026-108432 www.strix.ai
- ThreatINT: CVE-2026-108432 cve.threatint.com
- VulDB: CVE-2026-108432 vuldb.com
- Vulners: VULNRICHMENT CVE-2026-108432 vulners.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 31 Oct 2026, 16:26.
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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