Office Access: Remote code execution via heap-based buffer overflow
Summary
A heap-based buffer overflow in Microsoft Office Access allows an unauthorized attacker to execute code over a network. The CVSS vector requires user interaction, so a user must open a crafted file or otherwise trigger the flaw. Successful exploitation would affect confidentiality, integrity and availability of the system. CVSS 8.8 (High); Microsoft rates it as Important.
Affected
- Microsoft 365 Apps for Enterprise (32-bit and x64): 16.0.1 before the build listed on Microsoft's release page (the CVE record link is malformed)
- Microsoft Office LTSC 2021: 16.0.1 before 16.0.14334.21048
- Microsoft Office LTSC 2024: 16.0.0 before 16.0.17932.21140
- Access 2016 and Office 2019: Unknown.
Fixed in
- Microsoft Office LTSC 2021: 16.0.14334.21048
- Microsoft Office LTSC 2024: 16.0.17932.21140
- Microsoft 365 Apps for Enterprise: Unknown; check the MSRC advisory and Microsoft's Office release page.
Workaround
Unknown. No vendor-published workaround was found.
Exploitation
- No known exploitation in the wild and no public proof of concept at the time of research (2026-11-10).
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- CVSS exploit code maturity: Unproven (E:U).
Our recommendation
- Check the MSRC advisory and confirm the fixed build for each Office channel in use.
- Deploy the November 2026 Office security updates, prioritising machines with Access installed.
- Block macros and unknown attachments, and restrict opening Office files from the internet where feasible.
- Watch for CISA KEV listing or public proof of concept, and re-check NVD, which showed the CVE as Awaiting Analysis.
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 CVE-2026-111301 www.cve.org
- Microsoft Security Update Guide CVE-2026-111301 msrc.microsoft.com
- BleepingComputer: Microsoft November 2026 Patch Tuesday www.bleepingcomputer.com
- Newsbeep: CVE-2026-111301 severity www.newsbeep.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, 23:16.
Original description (NVD)
Heap-based buffer overflow in Microsoft Office Access 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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