Microsoft Office Word: Heap-based buffer overflow allows remote code execution
Summary
A heap-based buffer overflow in Microsoft Word, part of Microsoft Office and Microsoft 365 Apps, allows an unauthorized attacker to execute code over the network. The attacker needs a victim to open or interact with a crafted document, most likely an email attachment or download. Successful exploitation would give high impact on confidentiality, integrity and availability.
Affected
- Microsoft 365 Apps for Enterprise (16.0.1 before the fixed build listed in the MSRC advisory; fixed build not verified)
- 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)
- 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, check the MSRC advisory
- Microsoft Office 365 for Mac: 16.115.26110837
- Microsoft Office LTSC 2021: 16.0.14334.21048
- Microsoft Office LTSC 2024: 16.0.17932.21140 (from a third-party source, not yet verified with MSRC)
- Microsoft Office LTSC for Mac 2021 and 2024: 16.115.26110837
- Fixes were released with the November 2026 Patch Tuesday updates.
Workaround
No vendor workaround found. Install the update.
- Keep Protected View enabled.
- Block or quarantine document attachments from unknown senders.
- Restrict Office use on hosts that do not need it.
Exploitation
- No evidence of exploitation in the wild for this CVE.
- No public proof of concept found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- CVSS exploit code maturity is Unproven (E:U).
Our recommendation
- Install the November 2026 Office updates on all affected endpoints in the next maintenance window and treat this as high priority.
- Verify in the MSRC Security Update Guide that build numbers are at or above the fixed versions, especially for Microsoft 365 Apps and LTSC 2024.
- Prioritise staff who handle external documents and enforce Protected View and attachment filtering.
- Monitor for NVD analysis and any change in exploitation status.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-112733 msrc.microsoft.com
- CVE.org record CVE-2026-112733 (CNA: Microsoft) www.cve.org
- Strix CVE page CVE-2026-112733 (secondary) www.strix.ai
- Qualys: Microsoft Patch Tuesday November 2026 review blog.qualys.com
- NTCompatible: Microsoft November 2026 Patch Tuesday www.ntcompatible.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, 22:53.
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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