2021-36765 | CODESYS EtherNetIP null pointer dereference

By Max On Aug 8, 2021

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3.4	$0-$5k	0.59

A vulnerability classified as problematic was found in CODESYS EtherNetIP up to 4.0.x. This vulnerability affects an unknown code block. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-476. As an impact it is known to affect availability. CVE summarizes:

In CODESYS EtherNetIP before 4.1.0.0, specific EtherNet/IP requests may cause a null pointer dereference in the downloaded vulnerable EtherNet/IP stack that is executed by the CODESYS Control runtime system.

The weakness was released 08/05/2021. The advisory is shared for download at customers.codesys.com. This vulnerability was named CVE-2021-36765 since 07/16/2021. Access to the local network is required for this attack. The requirement for exploitation is a single authentication. There are neither technical details nor an exploit publicly available.

Upgrading to version 4.1.0.0 eliminates this vulnerability.

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