Microsoft Office Word: Stack-based buffer overflow allows remote code execution
Summary
A stack-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code over a network. The attack requires that a user opens a malicious Office file, typically received by email or download, so user interaction is needed. Code runs with the rights of the logged-in user, and the CVSS base score is 8.8 (high).
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 up to the fixed build listed in the Microsoft release notes (https://aka.ms/OfficeSecurityReleases)
- Office 365 for Mac: before 16.114.26101123
- Office LTSC 2021: before 16.0.14334.20974
- Office LTSC 2024: before 16.0.17932.21056
- Office LTSC for Mac 2021 and 2024: before 16.114.26101123 (listed by one mirror only)
- Build numbers are unverified; the sources conflict for LTSC 2024.
Fixed in
- Microsoft October 2026 security updates for Microsoft Office Word (exact builds: see MSRC advisory)
Workaround
Unknown. No vendor workaround is documented; apply the update.
Exploitation
- Not listed in CISA KEV at the time of research.
- CISA SSVC: Exploitation none, Automatable no.
- EPSS below 1%.
- No public exploit code reported by one aggregator; no evidence of in-the-wild exploitation found. Current status after publication: Unknown.
Our recommendation
- Confirm the installed Office build on each endpoint against the MSRC advisory.
- Verify that Microsoft 365 Apps and Mac clients have received the October 2026 updates.
- Check LTSC and on-premises installs manually.
- Keep Protected View enabled and filter Office attachments from untrusted senders at the mail gateway.
- Restrict macros where they are not required.
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-2026-108445 msrc.microsoft.com
- OpenCVE: CVE-2026-108445 app.opencve.io
- threatint: CVE-2026-108445 cve.threatint.com
- Strix: CVE-2026-108445 www.strix.ai
- TheHackerWire: CVE-2026-108445 www.thehackerwire.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 31 Oct 2026, 16:15.
Original description (NVD)
Stack-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.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.