Microsoft Office: Heap-based buffer overflow allows remote code execution
Summary
A heap-based buffer overflow in Microsoft Office (CWE-122) allows an unauthenticated attacker to execute code over a network. The CVSS 3.1 base score is 8.8. Exploitation requires user interaction, so the likely path is a crafted document delivered by phishing or a malicious attachment. The vendor record covers Microsoft 365 Apps for Enterprise, Office LTSC 2021, Office LTSC 2024 and Office for Mac.
Affected
- Microsoft 365 Apps for Enterprise: 16.0.1 up to the fixed build named at https://aka.ms/OfficeSecurityReleases (exact build unknown)
- Office 365 for Mac: before 16.114.26101123 (aggregator data, not verified)
- Office LTSC 2021: before 16.0.14334.20974 (aggregator data, not verified)
- Office LTSC 2024: before 16.0.17932.21056 (aggregator data, not verified)
- Office LTSC for Mac 2021 and 2024: before 16.114.26101123 (aggregator data, not verified)
Fixed in
- Microsoft 365 Apps for Enterprise: Unknown. Read the fixed build from the MSRC advisory.
- Office LTSC, Office for Mac: Versions listed above as fixed, not verified against MSRC.
- The CVE record and the offseq data indicate that an official vendor fix is available.
Workaround
- No vendor-specific workaround identified.
- Unknown whether MSRC lists an interim mitigation.
- Apply the latest vendor updates.
Exploitation
- CISA SSVC: exploitation none, automatable no, technical impact total.
- Not listed in the CISA KEV catalog.
- No public proof of concept or exploit code confirmed at the time of research.
- EPSS score: Unknown.
Our recommendation
- Patch Microsoft 365 Apps and Office LTSC and Mac installations as a priority.
- Confirm that automatic Microsoft 365 updates are running on all endpoints.
- Check LTSC and Mac installations separately, because they update through different channels.
- Verify all version numbers against the MSRC advisory before finalising client advice.
- Warn users about unsolicited documents and attachments until patching is complete.
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-2026-108444 msrc.microsoft.com
- OpenCVE: CVE-2026-108444 app.opencve.io
- Offseq Radar: CVE-2026-108444 radar.offseq.com
- ThreatInt: CVE-2026-108444 cve.threatint.com
- The Hacker Wire: CVE-2026-108444 www.thehackerwire.com
- Strix AI: CVE-2026-108444 www.strix.ai
- VulDB: CVE-2026-108444 vuldb.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, 16:24.
Original description (NVD)
Heap-based buffer overflow in Microsoft Office 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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