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 attack requires that a user interacts with the crafted content, for example by opening a malicious document. Microsoft 365 Apps, Office LTSC and Office for Mac versions are listed as affected in the CNA record. The CVSS base score is 8.8 (High), and the CNA record shows high impact on confidentiality, integrity and availability.
Affected
- Microsoft 365 Apps for Enterprise, 16.0.1 up to the fixed build (not stated in the CNA record)
- 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 (unverified against Microsoft)
- Microsoft Office LTSC for Mac 2021 and 2024, before 16.115.26110837 (unverified against Microsoft)
Fixed in
- Microsoft Office LTSC 2021: 16.0.14334.21048
- Microsoft Office 365 for Mac: 16.115.26110837
- Microsoft Office LTSC 2024: 16.0.17932.21140 (unverified)
- Microsoft 365 Apps for Enterprise: Unknown. Check the MSRC advisory.
Workaround
Unknown.
Exploitation
- No evidence of exploitation in the wild found at the time of writing.
- No public proof-of-concept found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
Our recommendation
- Install the November 2026 Office security updates on all Windows and Mac systems with affected Office versions as soon as possible.
- Verify the fixed build numbers on the MSRC advisory before rollout.
- Until patched, filter email attachments, keep Protected View enabled and avoid opening unsolicited documents.
- Monitor the MSRC advisory and CISA KEV for changes 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
- CVE.org CNA record CVE-2026-116925 www.cve.org
- Microsoft Security Update Guide CVE-2026-116925 msrc.microsoft.com
- CWE-122 Heap-based Buffer Overflow cwe.mitre.org
- Strix CVE-2026-116925 (secondary, unverified) 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 10 Nov 2026, 22:37.
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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