Microsoft Office Visio: Remote code execution via heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Office Visio allows an unauthorized attacker to execute code over a network. Exploitation requires a user to interact, most likely by opening a crafted Visio or Office file, for example from email. The CVSS base score is 8.8 (high), with high impact on confidentiality, integrity and availability.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 before the build listed at https://aka.ms/OfficeSecurityReleases
- Office LTSC 2021: 16.0.1 before 16.0.14334.21048
- Office LTSC 2024: 16.0.0 before 16.0.17932.21140
- Visio component: whether standalone Visio is affected is not confirmed by the CNA record.
Fixed in
- Office LTSC 2021: 16.0.14334.21048
- Office LTSC 2024: 16.0.17932.21140
- Microsoft 365 Apps for Enterprise: Unknown. Check the release page referenced by Microsoft.
Workaround
Unknown. No vendor workaround was found for this CVE.
Exploitation
- Exploited in the wild: no evidence found; CISA KEV status unconfirmed.
- Public proof of concept: none found.
- CISA SSVC: exploitation none, automatable no, technical impact total.
Our recommendation
- Confirm which Microsoft 365 or Office build each endpoint runs and whether Visio is installed.
- Deploy the November 2026 Microsoft security update to all Office and Visio clients, and verify the exact build on the MSRC page.
- Train users not to open unexpected Office or Visio files from email or downloads.
- Monitor CISA KEV and NVD for status changes, as NVD analysis is still pending.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Security Update Guide: CVE-2026-109496 (MSRC) msrc.microsoft.com
- CVE Record CVE-2026-109496 www.cve.org
- Strix AI: CVE-2026-109496 www.strix.ai
- Nessus plugin: related Visio click-to-run fixes (CVE-2026-102855 to 102857) vulners.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, 23:54.
Original description (NVD)
Heap-based buffer overflow in Microsoft Office Visio 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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