Technologies for mutual application isolation include a computing device having a processor with secure enclave support. The computing device loads an application image to a memory range within a predefined virtual address range and creates a secure enclave with the predefined virtual address range assigned to the secure enclave. The computing device validates control flow integrity of the secure enclave. To validate control flow integrity the computing device may validate that the memory pages of the secure enclave synchronously exit only to an allowed address. Additionally, to validate control flow integrity the computing device may validate an asynchronous exit point associated with an enclave entry instruction. After validating the control flow integrity, the computing device executes the secure enclave, which includes enforcing mutual isolation of the application image and the secure enclave using the secure enclave support of the processor. Other embodiments are described and claimed.