Microsoft Office Word: Remote code execution via heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Word allows a remote attacker to execute code on the affected system. Exploitation requires that a user opens a malicious document, typically received by email or download. Microsoft rates the flaw with CVSS 8.8 (High), and the impact on confidentiality, integrity and availability is high.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 before the fixed build referenced by Microsoft (exact build unknown)
- Microsoft Office 365 for Mac: 1.0.0 before 16.115.26110837
- Office LTSC 2021: 16.0.1 before 16.0.14334.21048
- Office LTSC 2024: 16.0.0 before 16.0.17932.21140 (secondary source, to be verified)
- Office LTSC for Mac 2021 and 2024: before 16.115.26110837 (unverified, only in a third-party aggregator)
Fixed in
- Office LTSC 2021: 16.0.14334.21048
- Office LTSC 2024: 16.0.17932.21140 (to be verified against MSRC)
- Microsoft 365 Apps and Office for Mac: Unknown, to be confirmed on MSRC
Workaround
Unknown. No vendor workaround was found in the sources reviewed.
Exploitation
- No evidence of exploitation in the wild found at the time of research.
- No public proof-of-concept found.
- Microsoft's exploit-maturity flag is 'unproven'.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
Our recommendation
- Install the November 2026 Office security updates on all endpoints, prioritising users who open external documents.
- Verify the fixed builds and severity rating on the MSRC Security Update Guide before setting deadlines.
- Filter malicious Office attachments at mail gateways and restrict macros and active content where possible.
- Monitor for exploitation indicators and follow up on any unexpected Word crashes or unusual child processes.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE.org record CVE-2026-110054 www.cve.org
- Microsoft Security Update Guide (MSRC) msrc.microsoft.com
- Strix CVE-2026-110054 www.strix.ai
- Zero Day Initiative November 2026 security update review www.zerodayinitiative.com
- Qualys 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, 23:47.
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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