Microsoft Office Word: Heap-based buffer overflow leads to remote code execution
Summary
Microsoft Office Word contains a heap-based buffer overflow that allows an unauthorized attacker to execute code over a network. Exploitation requires that a user opens a crafted document, for example one received by email or download. The CVSS 3.1 base score is 8.8 (High). No exploitation is known.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 before the fixed build (build number not confirmed)
- Microsoft Office 365 for Mac: 1.0.0 before 16.115.26110837
- Microsoft Office LTSC 2021: 16.0.1 before 16.0.14334.21048
- Microsoft Office LTSC 2024: 16.0.0 before 16.0.17932.21140 (unverified, from a third-party source)
- Microsoft Office LTSC for Mac 2021: 16.0.1 before 16.115.26110837
- Microsoft Office LTSC for Mac 2024: 16.0.0 before 16.115.26110837
Fixed in
- Microsoft 365 Apps for Enterprise: Unknown.
- Office 365 for Mac: 16.115.26110837 or later
- Office LTSC 2021: 16.0.14334.21048 or later
- Office LTSC 2024: 16.0.17932.21140 or later (unverified)
- Office LTSC for Mac 2021 and 2024: 16.115.26110837 or later
Workaround
Unknown. No vendor workaround was found. Apply the update.
Exploitation
No known exploitation. CISA SSVC assessment: exploitation none, not automatable, total technical impact.
Our recommendation
- Install the November 2026 Office security updates, prioritising Microsoft 365 Apps and Office LTSC.
- Check the fixed build for Microsoft 365 Apps in the MSRC advisory or release notes.
- Keep Protected View enabled and block or sandbox untrusted attachments.
- Make sure Microsoft 365 automatic updates are working.
- Re-check the exploitation status later, as this CVE was published today.
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-2026-112728 msrc.microsoft.com
- CVE Record CVE-2026-112728 www.cve.org
- Strix AI: CVE-2026-112728 (third-party, unverified versions) www.strix.ai
- Zero Day Initiative: November 2026 Security Update Review www.zerodayinitiative.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.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.