Microsoft Office Word: Remote Code Execution via heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network. Exploitation requires the user to open a crafted document, typically delivered by email or download. No prior account is needed. The CVSS base score is 8.8 (High).
Affected
- Microsoft 365 Apps for Enterprise (32-bit and x64): 16.0.1 before the build listed on the Microsoft Office security release page
- Microsoft Office LTSC 2021 (32-bit and x64): 16.0.1 before 16.0.14334.21048
- Microsoft Office LTSC 2024 (32-bit and x64): 16.0.0 before 16.0.17932.21140
- Office 2016, Office 2019 and other perpetual builds: not listed in the CNA record; status unknown
Fixed in
- Microsoft 365 Apps for Enterprise: Unknown (see the Microsoft Office security release page)
- Microsoft Office LTSC 2021: 16.0.14334.21048 or later
- Microsoft Office LTSC 2024: 16.0.17932.21140 or later
Workaround
Unknown. No Microsoft-documented workaround was identified. Patching is the fix.
Exploitation
- No active exploitation known at the time of research; CISA SSVC assessment: exploitation none
- CVSS exploit code maturity: Unproven (E:U)
- Public proof of concept: Unknown
- CISA KEV status: not verified directly
Our recommendation
- Patch Microsoft 365 Apps and Office LTSC installations in the next regular update cycle
- Check the Microsoft Office security release page for the fixed Microsoft 365 build
- Block or quarantine Office attachments from unknown senders
- Keep Protected View enabled for files from the internet
- Verify the fixed builds and exploitation status on MSRC, NVD and CISA KEV before finalising the patch plan
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: CVE-2026-111290 msrc.microsoft.com
- CVE.org record CVE-2026-111290 www.cve.org
- Strix: CVE-2026-111290 (secondary) www.strix.ai
- Newsbeep: Microsoft November 2026 Patch Tuesday (secondary) www.newsbeep.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, 23:17.
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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