Unknown criminals are exploiting a maximum-severity vulnerability in Node-RED, a flow-based programming tool that is widely used in critical infrastructure, to deploy a flow that downloads and runs a Linux bot. Node-RED is commonly used for workflow automation in industrial control systems (ICS) and operational technology (OT) environments. It’s built on top of Node. js and is used in commercial products including Siemens SIMATIC IoT2050 . In August, Siemens assigned the vulnerability identifier – CVE-2026-58115 – to describe the bug and explain its perfect 10-out-of-10 CVSS rating. Affected Siemens devices do not enforce authentication on the Node-RED HTTP interface, allowing unauthenticated access to programming nodes that can execute system commands on the device. This means unauthenticated remote attackers can create malicious flows, which is what VulnCheck researchers began documenting last Friday. “On October 30, 2026, one of our canaries caught an attacker exploiting CVE-2026-58115,” VulnCheck researcher Patrick Garrity warned in a Monday advisory, adding that two Node-RED built-in nodes make this vulnerability “trivial to weaponize.” One is an inject node, which fires a message either on a schedule or once at startup. The second, an exec node, can run shell commands. “Wire one to the other and the flow executes a command as soon as it is deployed, with no further interaction,” Garrity said. Plus, these exploits come as criminals increasingly look to target internet-exposed OT and ICS devices , allowing their cyberattacks to impact the physical world and produce real-life harm. Case in point: the ongoing refrigeration controller hacks across Europe and the attacks on wa ter systems across at least 12 US states over the summer. The activity observed by VulnCheck came from a single IP address, 4. 201. 105[. ]116, which sits in Microsoft’s AS8075 network and geolocates to Brazil. “It didn’t just scan us…