Microsoft Office Word: Remote code execution through integer overflow
Summary
A integer overflow (CWE-190) and use-after-free (CWE-416) in Microsoft Office Word allow code execution when a crafted document is processed. An unauthenticated attacker can exploit this over a network, but only if a user opens the malicious file, for example one received by email or download. CISA SSVC lists no exploitation, and the vendor's exploitation status could not be verified from the sources.
Affected
- Microsoft 365 Apps for Enterprise (exact affected range per MSRC; CNA record lists 16.0.1 up to the fixed release)
- Microsoft Office 365 for Mac: versions before 16.114.26101123
- Office LTSC 2021: versions before 16.0.14334.20974 (unverified)
- Office LTSC 2024: versions before 16.0.17932.21056 (unverified)
- Office LTSC for Mac 2021 and 2024: versions before 16.114.26101123
Fixed in
- Office 365 for Mac and LTSC for Mac: 16.114.26101123 (per CNA record)
- Office LTSC 2021: 16.0.14334.20974 (unverified, from third-party aggregator)
- Office LTSC 2024: 16.0.17932.21056 (unverified, from third-party aggregator)
- Microsoft 365 Apps monthly channels: check the MSRC page for the exact build per update branch; the fixed builds could not be verified
Workaround
- No vendor workaround found in the sources reviewed. Patching is the fix.
- Generic risk reduction: block attachments from external senders and keep Protected View enabled for internet-sourced files.
Exploitation
- No confirmed exploitation in the sources reviewed; no CISA KEV listing found.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- Public proof of concept: none found.
- EPSS from a mirror is about 0.005 (low). Verify the vendor exploitation flag on MSRC.
Our recommendation
- Apply the October 2026 Office security updates to all Windows and Mac clients.
- Prioritise users who regularly open external documents.
- Confirm the exact fixed build for your update channel (Current, Monthly Enterprise or LTSC) on the MSRC page before rollout.
- Keep Protected View enabled and filter email attachments from external senders.
- Recheck the CISA KEV catalogue before the next patch window.
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-105715 msrc.microsoft.com
- Microsoft Office for Mac release notes learn.microsoft.com
- NVD mirror (Vulners): CVE-2026-105715 vulners.com
- CVE list mirror (Vulners): CVE-2026-105715 vulners.com
- Microsoft CVE mirror (Vulners): MS:CVE-2026-105715 vulners.com
- Strix: CVE-2026-105715 www.strix.ai
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 2 Nov 2026, 19:35.
Original description (NVD)
Integer overflow or wraparound 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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