Microsoft Office Word: Heap-based buffer overflow allows code execution
Summary
A heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network. Exploitation requires a user to interact with the attack, most likely by opening a specially crafted document. Successful exploitation can give the attacker the rights of the logged-in user, which is why the CVSS score is 8.8.
Affected
- Microsoft 365 Apps for Enterprise (16.0.1 up to the fixed build listed at https://aka.ms/OfficeSecurityReleases)
- Microsoft Office 365 for Mac (1.0.0 to < 16.115.26110837)
- Microsoft Office LTSC 2021 (16.0.1 to < 16.0.14334.21048)
- Microsoft Office LTSC 2024 (16.0.0 to < 16.0.17932.21140)
- Microsoft Office LTSC for Mac 2021 (16.0.1 to < 16.115.26110837)
- Microsoft Office LTSC for Mac 2024 (16.0.0 to < 16.115.26110837; listed in only one of the two data snapshots, verify on MSRC)
Fixed in
- Microsoft 365 Apps: see https://aka.ms/OfficeSecurityReleases for the current build of your channel.
- LTSC and Mac builds: the upper bounds above come from the CNA data and are not yet confirmed as fixed builds by Microsoft. Check the MSRC advisory before relying on them.
Workaround
Unknown. No vendor-stated workaround is available.
- Until patched, keep Protected View enabled, block or quarantine Office files from untrusted email and downloads, and restrict macro and file types at the mail gateway (general guidance, not from the vendor).
Exploitation
- Exploited in the wild: Unknown.
- Public proof of concept: Unknown.
- CISA SSVC assessment (CNA record): Exploitation none, Automatable no, Technical Impact total.
Our recommendation
- Check the MSRC advisory for the confirmed fixed builds and install the security update for Microsoft 365, Office 2021/2024 and Office for Mac as soon as possible.
- Inventory all Office clients and their versions, and identify unpatched LTSC or Mac installations.
- Filter Office attachments at the mail gateway and restrict downloads of documents from untrusted sources.
- Monitor for unusual process activity started by Word and keep Protected View enabled.
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: CVE-2026-116722 msrc.microsoft.com
- CVE Record: CVE-2026-116722 www.cve.org
- Strix: CVE-2026-116722 (version data, 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, 22:37.
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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