Critical Vulnerabilities Dubbed URGENT/11 Place Devices Running VxWorks at Risk of RCE Attacks

Ryan Seguin

Eleven vulnerabilities, including RCEs, denials of service, information leaks and logical flaws, were recently disclosed, impacting the RTOS VxWorks


The Armis Research Team has released an advisory for URGENT/11, which contains six critical RCE and five additional vulnerabilities in VxWorks, a Real-Time Operating System (RTOS) found in over 2 billion devices, including critical industrial, medical and enterprise hardware. Wind River, the maintainer of VxWorks, released patches on July 19 for all 11 of the vulnerabilities.


VxWorks is an RTOS found in a wide array of devices like firewalls, medical equipment and industrial control systems. The vulnerabilities found affect VxWorks’ TCP/IP stack (IPnet) and could allow attackers to circumvent Network Address Translation (NAT) and Firewalls via maliciously crafted IP packets. Wind River acquired the IPnet networking stack in 2006. Prior to this, the stack was licensed and used by other real-time operating system vendors, which potentially widens the number of affected devices that have yet to be patched. The scale and potential impact of these vulnerabilities create similar threats on par with the likes of WannaCry and ETERNALBLUE.

The following video from Armis provides an overview of URGENT/11 and its potential impact:

From Wind River's URGENT/11 security advisory, the following vulnerabilities and their respective details are:

CVE CVSSv3 Score Component Title CVE-2019-12256 9.8 TCP/IP Stack Stack overflow in the parsing of IPv4 packets’ IP options CVE-2019-12257 8.8 DHCP Client Heap overflow in DHCP Offer/ACK parsing inside ipdhcpc CVE-2019-12255 9.8 TCP Urgent Pointer TCP Urgent Pointer = 0 leads to integer underflow CVE-2019-12260 9.8 TCP Urgent Pointer TCP Urgent Pointer state confusion caused by malformed TCP AO option CVE-2019-12261 8.8 TCP Urgent Pointer TCP Urgent Pointer state confusion during connect() to a remote host CVE-2019-12263 8.1 TCP Urgent Pointer TCP Urgent Pointer state confusion due to race condition CVE-2019-12258 7.5 TCP Connection DoS of TCP connection via malformed TCP options CVE-2019-12259 6.3 TCP/IP Stack DoS via NULL dereference in IGMP parsing CVE-2019-12262 7.1 ARP Handler Handling of unsolicited Reverse ARP replies (Logical Flaw) CVE-2019-12264 7.1 DHCP Logical flaw in IPv4 assignment by the ipdhcpc DHCP client CVE-2019-12265 5.4 IGMP IGMP Information leak via IGMPv3 specific membership report

Proof of Concept

While no Proof of Concept (PoC) code has been released for these vulnerabilities, the Armis team has provided two videos demonstrating how an attacker could compromise internal assets from other internet-facing devices:


Organizations and individual users will need to apply updates from their respective device vendors in order to fix these vulnerabilities within their environments. Vendors like SonicWall and Xerox have reportedly released updates for their affected devices. Detection and mitigation may take some time, however, given the  sheer magnitude of the number of devices utilizing VxWorks.

Tenable will add active and passive plugins as patches and updates become available from different vendors. Our OS Identification plugin can enumerate hosts running VxWorks, which will be available in the plugin output section in the scan results for a given asset. Tenable Nessus Network Monitor (NNM) currently offers multiple VxWorks detection plugins, and proactively detects assets that may be running vulnerable versions of VxWorks.

For users seeking guidance on configuring NNM and creating useful notifications for VxWorks devices, please see our NNM configuration and usage documentation or reach out to our support team at

Identifying affected systems

A list of plugins to identify these vulnerabilities will appear here as they’re released. Please note that vulnerability detection plugin creation also relies on vendor support for any given device. We encourage organizations to examine the plugin output section of our informational detection plugins in their scan results to identify vulnerable systems in addition to scanning with direct vulnerability detection plugins.

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Published on Jul 29, 2019

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