Microsoft Office Word: Remote Code Execution via heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code on a vulnerable system over the network. The attack requires user interaction, typically a user opening a crafted document received by email or file download, but no privileges. CVSS 3.1 base score is 8.8 (High).
Affected
- Microsoft 365 Apps for Enterprise (16.0.1 up to the fixed build listed on the MSRC page)
- Microsoft Office 365 for Mac (1.0.0 before 16.115.26110837)
- Microsoft Office LTSC 2021 (16.0.1 before 16.0.14334.21048)
- Microsoft Office LTSC 2024 (16.0.0 before the fixed build; Unknown from the Microsoft record)
- Microsoft Office LTSC for Mac 2021 (16.0.1 before 16.115.26110837)
- Microsoft Office LTSC for Mac 2024 (16.0.0 before 16.115.26110837)
Fixed in
- Microsoft 365 Apps for Enterprise: Unknown; see MSRC advisory
- Office 365 for Mac: 16.115.26110837
- Office LTSC 2021: 16.0.14334.21048
- Office LTSC 2024: Unknown from Microsoft sources (third-party source reports 16.0.17932.21140, not confirmed)
- Office LTSC for Mac 2021 and 2024: 16.115.26110837
Workaround
Unknown. No vendor workaround was found; apply the security update.
Exploitation
- No evidence of exploitation in the wild at release.
- No public proof of concept found; CVSS Exploit Code Maturity is Unproven (E:U).
- CISA SSVC: exploitation none, automatable no, technical impact total.
Our recommendation
- Verify installed Office builds on all systems against the MSRC advisory and install the November 2026 security updates.
- Prioritise staff who open external documents and check Microsoft 365 auto-update status.
- Update Office LTSC and Mac installations manually, as they typically do not update automatically.
- Keep email attachment filtering and file download scanning enabled.
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 (Microsoft CNA) www.cve.org
- MSRC Security Update Guide msrc.microsoft.com
- Strix aggregator (secondary) www.strix.ai
- Cryptika Patch Tuesday summary www.cryptika.com
- Tenable Patch Tuesday summary www.tenable.com
- Qualys Patch Tuesday 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, 23:04.
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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