The CODESYS Gateway Client allocates memory based solely on a size field supplied in a gateway response. Because no upper limit is enforced, an attacker can send a response with an enormous size value, causing the process to consume excessive memory and eventually fail. The flaw is an uncontrolled memory allocation, identified as CWE‑770, and its primary consequence is a denial‑of‑service that leads to total loss of availability for the component.

All listed CODESYS products carry this flaw. The affected items are the Development System 3, Edge Gateway for Linux, Edge Gateway for Windows, Gateway, HMI (SL), OPC DA Server SL, PLCHandler, and Runtime Toolkit. No version‑level restrictions were specified, so every installed instance is potentially vulnerable until a patch is applied.

With a CVSS score of 8.7 the vulnerability is assessed as high severity. The EPSS score is not available, so the exact likelihood of exploitation cannot be quantified; however, the condition requires only an unauthenticated remote attacker who can control a malicious gateway. The weakness is not currently listed in the CISA KEV catalog, indicating no confirmed public exploitation as of the data available. The most probable attack vector is remote network traffic, whereby the attacker crafts gateway responses containing an oversized size field to trigger memory exhaustion.