Profinet-IO (PNIO) stack versions prior V06.00 do not properly limit internal resource allocation when multiple legitimate diagnostic package requests are sent to the DCE-RPC interface. This could lead to a denial of service condition due to lack of memory for devices that include a vulnerable version of the stack. The security vulnerability could be exploited by an attacker with network access to an affected device. Successful exploitation requires no system privileges and no user interaction. An attacker could use the vulnerability to compromise the availability of the device.
https://cert-portal.siemens.com/productcert/html/ssa-780073.html
https://cert-portal.siemens.com/productcert/pdf/ssa-780073.pdf