CVE-2020-12494

CVE-2020-12494 is a medium-severity vulnerability in Beckhoff Twincat Driver with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-459.

Key facts

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.

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 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2020-12494 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-12494?
CVE-2020-12494 primarily affects Beckhoff Twincat Driver. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-12494?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-12494 published?
CVE-2020-12494 was published on 2020-06-16 and last updated on 2026-06-17.

References

Affected products (2)

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