CVE-2012-6436 Rockwell Automation ControlLogix PLC Improper Input Validation

High 7.8 Published 24 Jan 2013 Updated 3 Jun 2026

An attacker can send malformed CIP packets to Rockwell PLCs to cause a buffer overflow and crash the CPU, resulting in denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2012-6436?

CVE-2012-6436 is a high-severity memory corruption vulnerability in Rockwell Automation 1756-ENBT, 1756-EWEB, 1768-ENBT, 1768-EWEB communication modules, published on 24 Jan 2013. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

The device does not properly validate the data being sent to the buffer. An attacker can send a malformed CIP packet to Port 2222/TCP, Port 2222/UDP, Port 44818/TCP, or Port 44818/UDP, which creates a buffer overflow and causes the CPU to crash. Successful exploitation of this vulnerability could cause loss of availability and a disruption in communications with other connected devices.

Rockwell Automation EtherNet/IP products; 1756-ENBT, 1756-EWEB, 1768-ENBT, and 1768-EWEB communication modules; CompactLogix L32E and L35E controllers; 1788-ENBT FLEXLogix adapter; 1794-AENTR FLEX I/O EtherNet/IP adapter; ControlLogix 18 and earlier; CompactLogix 18 and earlier; GuardLogix 18 and earlier; SoftLogix 18 and earlier; CompactLogix controllers 19 and earlier; SoftLogix controllers 19 and earlier; ControlLogix controllers 20 and earlier; GuardLogix controllers 20 and earlier; and MicroLogix 1100 and 1400

Weakness: CWE-119

Which versions are affected by CVE-2012-6436?

It affects 17 products.

Products include Rockwellautomation 1756-Enbt, Rockwellautomation 1756-Eweb, Rockwellautomation 1768-Enbt, Rockwellautomation 1768-Eweb, Rockwellautomation 1794-Aentr Flex I\/O Ethernet\/Ip Adapter, Rockwellautomation Compactlogix and 11 more.

How do I fix CVE-2012-6436?

No fix has been published for CVE-2012-6436 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2012-6436 being exploited?

There is no known exploitation of CVE-2012-6436 in the wild and no public exploit code.

Sources

Also known as GHSA-4874-wfww-j2mq.