The Schneider Electric M340 BMXNOE01xx and BMXP3420xx PLC modules allow remote authenticated users to cause a denial of service (module crash) via crafted FTP traffic, as demonstrated by the FileZilla FTP client.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.