Microsoft Office Access: Heap-based buffer overflow allows code execution
Summary
A heap-based buffer overflow in Microsoft Office Access allows remote code execution. A user must open a specially crafted file, for example one received by email or downloaded, before an attacker can run code. No authentication is needed, and Microsoft does not report public disclosure of the vulnerability.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 up to the fixed build (exact build unknown)
- Office LTSC 2021: 16.0.1 up to 16.0.14334.20974
- Office LTSC 2024: 16.0.0 up to 16.0.17932.21056
- Office 2019, Office 2021, Office 2024 and Microsoft 365 Apps for business: listed in Microsoft's release notes, build numbers unknown
Fixed in
- Office LTSC 2021: 16.0.14334.20974 or later
- Office LTSC 2024: 16.0.17932.21056 or later
- Microsoft 365 Apps: Unknown; check the October 13, 2026 release notes at aka.ms/OfficeSecurityReleases
Workaround
- None found in the sources. Until patched, do not open Access files (.accdb/.mdb) from unknown senders or untrusted downloads, keep Protected View enabled, and restrict or sandbox inbound attachments.
Exploitation
- Microsoft: not publicly disclosed.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- Not listed in CISA KEV in the checked source; no confirmed exploitation in the wild found.
- No public proof of concept found.
Our recommendation
- Install the October 13, 2026 Office security updates on all hosts with Access, starting with LTSC 2021 and 2024 builds below the fixed versions, and confirm the Microsoft 365 Apps build on the MSRC page.
- Until patched, do not open Access databases from unknown senders or untrusted downloads; keep Protected View enabled.
- Monitor the MSRC page and CISA KEV for changes.
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-2026-102849 msrc.microsoft.com
- Microsoft 365 Apps security updates (release notes) learn.microsoft.com
- Microsoft Patch Tuesday October 2026 review (Qualys) threatprotect.qualys.com
- CVE-2026-102849 mirror (OffSeq Radar) radar.offseq.com
- CVE-2026-102849 (Vulners, Microsoft MSCVE) 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 31 Oct 2026, 19:30.
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.
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.