CVE-2020-12494 json
Beckhoff: Etherleak in TwinCAT RT network driver
published 2020-06-16 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-4796
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.0%
- EPSS 1.0% chance of exploitation in 30 days, percentile 63%
- public exploits
- 0
- none known
Summary
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.
Exploit prediction
1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:P/I:N/A:N |
Affected products
- Beckhoff TwinCat Driver for Intel 8254x (Tcl8254x.sys)
- Beckhoff TwinCat Driver for Intel 8255x (Tcl8255x.sys)
Classification
- Weakness
-
- CWE-459 Incomplete Cleanup
References
-
cert.vde.com
/en-us/advisories/vde-2020-019
third-party-advisory
Sources
- CVE List CVE-2020-12494
- NVD CVE-2020-12494
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