Microsoft Windows OLE: Heap-based buffer overflow allows local privilege escalation
Summary
A heap-based buffer overflow in the Windows OLE component allows a locally authorized user with low privileges to elevate their privileges, potentially to SYSTEM. An attacker needs an existing foothold on the device, for example through phishing, a malicious document or a stolen low-privilege account. The CVSS vector rates the impact on confidentiality, integrity and availability as high.
Affected
- Windows 10 Version 1607: 10.0.14393.0 to < 10.0.14393.9612
- Windows Server 2016: 10.0.14393.0 to < 10.0.14393.9612
- Other affected Windows 10, Windows 11 and Windows Server 2012/2012 R2 versions are listed in the CVE record and the MSRC advisory.
Fixed in
- Windows 10 Version 1607 and Windows Server 2016: build 10.0.14393.9612 or later, according to the CVE record.
- The exact KB number for Windows 10 1607 is unknown; confirm it in the MSRC advisory.
Workaround
- No vendor-published workaround identified.
- Limit local user rights to the minimum required for each job role.
- Enable Data Execution Prevention and Exploit Protection for Windows OLE processes.
Exploitation
- No evidence of exploitation in the wild.
- No public proof of concept found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- EPSS score: 0.00341.
Our recommendation
- Install the October 2026 security update on all affected systems, starting with Windows 10 1607 and Windows Server 2016 devices.
- Confirm that Windows 10 1607 devices still receive updates; replace them if they do not.
- Restrict local logons and standard user rights on shared systems and terminal servers.
- Monitor for unexpected privilege changes and new local administrator accounts.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows OLE
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5127648, KB5126651, KB5126655, KB5126657, KB5126646, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-70138 msrc.microsoft.com
- OpenCVE: CVE-2026-70138 app.opencve.io
- Rapid7 via Vulners: CVE-2026-70138 (EPSS) vulners.com
- NVD mirror via Vulners: CVE-2026-70138 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 2 Nov 2026, 04:06.
Original description (NVD)
Heap-based buffer overflow in Windows OLE allows an authorized attacker to elevate privileges locally.
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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