Microsoft Office Word: Heap-based buffer overflow allows remote code execution
Summary
A heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network. The CVSS base score is 8.8 (High). Exploitation requires a user to take an action, such as opening a crafted document, delivered for example by email or download.
Affected
- Microsoft 365 Apps for Enterprise (32-bit and x64): 16.0.1 before the fix linked from the Microsoft security release page (fixed build unknown)
- Microsoft Office 365 for Mac: 1.0.0 before 16.115.26110837
- Microsoft Office LTSC 2021 (32-bit and x64): 16.0.1 before 16.0.14334.21048
- Microsoft Office LTSC 2024: 16.0.0 before 16.0.17932.21140 (unconfirmed, from a third-party source)
- Microsoft Office LTSC for Mac 2021 and 2024: before 16.115.26110837 (LTSC for Mac 2024 partly unconfirmed)
Fixed in
- Microsoft 365 Apps for Enterprise: Unknown. See the Microsoft security release page.
- Microsoft Office 365 for Mac: 16.115.26110837
- Microsoft Office LTSC 2021: 16.0.14334.21048
- Microsoft Office LTSC 2024: 16.0.17932.21140 (unconfirmed)
- Microsoft Office LTSC for Mac 2021 and 2024: 16.115.26110837 (to be verified)
Workaround
Unknown. No vendor workaround was found in the sources.
- Until patched, avoid opening unsolicited Word documents, especially from email or downloads.
- Keep Protected View enabled.
Exploitation
- The CVE record's temporal vector includes E:U (exploit code maturity unproven).
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- No in-the-wild exploitation or public proof-of-concept known at publication.
Our recommendation
- Patch Microsoft 365 Apps and Office LTSC builds in the next maintenance window, prioritising this update.
- Verify the fixed builds on the MSRC update guide before rollout.
- Until patched, handle documents from external sources with caution and keep Protected View enabled.
- Check NVD and CISA KEV for later changes, since the CVE was published today.
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: CVE-2026-112730 msrc.microsoft.com
- CVE Record: CVE-2026-112730 www.cve.org
- Strix: CVE-2026-112730 (secondary, unverified) www.strix.ai
- Microsoft November 2026 Patch Tuesday coverage cybersecuritynews.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, 22:52.
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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