Microsoft Office Word: Heap-based buffer overflow allows remote code execution
Summary
A heap-based buffer overflow (CWE-122) in Microsoft Office Word allows an unauthorized attacker to execute code over a network. The victim must open a crafted document, for example an email attachment or a downloaded file, so user interaction is required. The CVSS 3.1 base score is 8.8 (High), with high impact on confidentiality, integrity and availability. No exploitation has been identified in the sources reviewed.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 up to the fixed build (exact build unknown, as the CVE record lists no valid build number)
- Microsoft Office 365 for Mac: 1.0.0 to before 16.115.26110837
- Microsoft Office LTSC 2021: 16.0.1 to before 16.0.14334.21048
- Microsoft Office LTSC 2024: 16.0.0 to before 16.0.17932.21140
- Microsoft Office LTSC for Mac 2021: 16.0.1 to before 16.115.26110837
- Microsoft Office LTSC for Mac 2024: 16.0.0 to before 16.115.26110837
Fixed in
- Office LTSC 2021: 16.0.14334.21048
- Office LTSC 2024: 16.0.17932.21140
- Office 365 for Mac and Office LTSC for Mac 2021/2024: 16.115.26110837
- Microsoft 365 Apps for Enterprise: Unknown; check the MSRC Security Update Guide
Workaround
Unknown. No vendor workaround was identified in the sources reviewed. Check the MSRC page for mitigation text.
- Keep Protected View enabled for files from the internet or email (general measure, not confirmed for this CVE).
Exploitation
- No evidence of exploitation in the wild was found.
- No public proof of concept was found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- CISA KEV status: Unknown; check the catalog directly.
Our recommendation
- Check the MSRC Security Update Guide and confirm the fixed build for each Office channel in use.
- Install the November 2026 Office updates on all Word installations, starting with users who handle email attachments and external documents.
- Keep Protected View enabled and record Office build numbers in your inventory.
- Recheck CISA KEV and vendor status within 48 hours.
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 (listed reference, not retrieved) msrc.microsoft.com
- strix.ai CVE-2026-112717 (third-party, unverified) www.strix.ai
- Qualys: Microsoft Patch Tuesday November 2026 review blog.qualys.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, 23:05.
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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