CVE-2020-12494: Beckhoff's TwinCAT RT network driver for Intel 8254x and 8255x is providing EtherCAT functionality. The driver implements real-time features. Except f...

Description

Beckhoff's TwinCAT RT network driver for Intel 8254x and 8255x is providing EtherCAT functionality. The driver implements real-time features. Except for Ethernet frames sent from real-time functionality, all other Ethernet frames sent through the driver are not padded if their payload is less than the minimum Ethernet frame size. Instead, arbitrary memory content is transmitted within in the padding bytes of the frame. Most likely this memory contains slices from previously transmitted or received frames. By this method, memory content is disclosed, however, an attacker can hardly control which memory content is affected. For example, the disclosure can be provoked with small sized ICMP echo requests sent to the device.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

1.01%

58.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Beckhoff	Twincat Driver	<= 3.1.0.3603
Beckhoff	Twincat	<= 3.1.0.3512
Beckhoff	Twincat	<= 2.11.0.2120
Beckhoff	Twincat	<= 3.1.0.3600
Beckhoff	Twincat	<= 3.1.0.3500
Beckhoff	Twincat	<= 2.11.0.2117

References

https://cert.vde.com/en-us/advisories/vde-2020-019Third Party Advisory
https://cert.vde.com/en-us/advisories/vde-2020-019Third Party Advisory

Timeline

Published: Jun 16, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-12494?

Beckhoff's TwinCAT RT network driver for Intel 8254x and 8255x is providing EtherCAT functionality. The driver implements real-time features. Except for Ethernet frames sent from real-time functionality, all other Ethernet frames sent through the driver are not padded if their payload is less than the minimum Ethernet frame size. Instead, arbitrary memory content is transmitted within in the padding bytes of the frame. Most likely this memory contains slices from previously transmitted or received frames. By this method, memory content is disclosed, however, an attacker can hardly control which memory content is affected. For example, the disclosure can be provoked with small sized ICMP echo requests sent to the device.

How severe is CVE-2020-12494?

CVE-2020-12494 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 1.01% probability of exploitation in the next 30 days.

How do I fix CVE-2020-12494?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.