SAP Gateway (SAP KERNEL 32 NUC, SAP KERNEL 32 Unicode, SAP KERNEL 64 NUC, SAP KERNEL 64 Unicode 7.21, 7.21EXT, 7.22 and 7.22EXT; SAP KERNEL 7.21, 7.22, 7.45, 7.49 and 7.53) allows an attacker to prevent legitimate users from accessing a service, either by crashing or flooding the service.