A method of securely executing a Just-In-Time (JIT) compiled code in a runtime environment, comprising using one or more processors for receiving from a JIT executing process a request to compile in runtime a code segment, initiating a JIT compiling process to compile the code segment in order to generate an executable code segment, storing the executable code segment in a shared memory and providing to the JIT executing process a pointer to the executable code segment in the shared memory. Wherein the JIT executing process having read-execute access rights to the shared memory and the JIT executing process and the JIT compiling process are different processes.