Beckhoff TcRouter.sys: Local access to physical memory via exposed IOCTLs
Summary
TcRouter.sys is a Windows kernel driver used by Beckhoff's TwinCAT automation software. Exposed IOCTL functions lack sufficient access control, so a local attacker with low privileges can move arbitrary physical memory content. The vendor states that this leads to full compromise of the affected devices. The attack requires a local foothold, for example through phishing, malware or a compromised user account, and is not directly reachable from the internet.
Affected
- TcRouter.sys for Windows on x64 and x86: 1.0.0 up to before 3.1.0.2365 - TwinCAT.XAR.Base.KM: 3.16.29 and versions before 3.18.1 (as listed in the CVE record)
Fixed in
- TcRouter.sys for Windows on x64 and x86: 3.1.0.2365 - TwinCAT.XAR.Base.KM: 3.18.1 (confirm both in the Beckhoff/CERT@VDE advisory)
Workaround
No workaround documented in the sources reviewed. Check the vendor advisory for further mitigations.
Exploitation
- Not known to be exploited. - No public proof of concept found. - VulDB lists the exploit status as not defined.
Our recommendation
- Inventory all Windows hosts with TwinCAT or TcRouter.sys, including the TwinCAT.XAR.Base.KM branch. - Compare installed versions with the fixed versions after checking the Beckhoff/CERT@VDE advisory. - Plan the update on each affected host following Beckhoff guidance. - Until patched, restrict local logon on these hosts, keep EDR active and keep TwinCAT machines off general office networks.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CERT@VDE advisory VDE-2026-087 www.certvde.com
- CVE Record CVE-2026-18769 www.cve.org
- VulDB entry 435706 vuldb.com
- OffSeq radar entry CVE-2026-18769 radar.offseq.com
- Threatint CVE-2026-18769 cve.threatint.com
- Beckhoff security information www.beckhoff.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 11 Nov 2026, 10:22.
Original description (NVD)
A local low privileged attacker can move arbitrary physical memory content via TcRouter.sys because of exposed IOCTL function calls resulting in a full compromise of the affected devices.
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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