Microsoft Office Word: Remote code execution via heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Word, part of Microsoft 365 Apps, Office LTSC and Office for Mac, allows an unauthenticated attacker to execute code over the network. The attack requires the victim to act, for example by opening a crafted Word document received by email or download. The CVSS 3.1 base score is 8.8 (High). CISA SSVC lists exploitation as none and automatable as no.
Affected
- Microsoft 365 Apps for Enterprise (32-bit and x64): from 16.0.1 up to the fixed build listed by Microsoft
- Office for Mac 365: from 1.0.0 before 16.115.26110837
- Office LTSC 2021 (32-bit and x64): from 16.0.1 before 16.0.14334.21048
- Office LTSC 2024: listed as affected from 16.0.0; exact fixed build not confirmed
- Office LTSC for Mac 2021 and 2024: before 16.115.26110837
Fixed in
- Microsoft 365 Apps for Enterprise: Unknown (see MSRC advisory)
- Office LTSC 2021: 16.0.14334.21048 (CVE record)
- Office LTSC 2024: Unknown (third-party sources state 16.0.17932.21140, not verified)
- Office for Mac and LTSC for Mac: 16.115.26110837 (CVE record)
Workaround
Unknown. No vendor-documented workaround was found. Install the November 2026 Microsoft 365 and Office security update.
Exploitation
- No evidence of exploitation in the wild found for this CVE.
- No public proof of concept found.
- Microsoft patched this CVE in its November 2026 Patch Tuesday release.
Our recommendation
- Install the November 2026 security update on all Microsoft 365, Office LTSC and Office for Mac installations and verify the installed build.
- Give priority to mail-facing users and to LTSC installations, which are often updated less frequently.
- Check the MSRC advisory for the exact fixed builds, especially for Microsoft 365 and LTSC 2024.
- Monitor for phishing with Office attachments and consider attachment filtering.
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 advisory CVE-2026-111294 msrc.microsoft.com
- CVE.org record CVE-2026-111294 www.cve.org
- Strix CVE-2026-111294 details www.strix.ai
- Tenable: Microsoft November 2026 Patch Tuesday www.tenable.com
- Qualys: Microsoft Patch Tuesday November 2026 review blog.qualys.com
- Rescana: Microsoft Patch Tuesday November 2026 www.rescana.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, 23:18.
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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