OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 4.3.0 and prior to version 4.11.0, a type confusion vulnerability exists in OP-TEE OS when processing an FFA_MEM_SHARE request from the normal world. This only applies when OP-TEE is configured as an SPMC for S-EL0 SPs, that is, with CFG_CORE_SEL1_SPMC=y and CFG_SECURE_PARTITION=y. Version 4.11.0 fixes the issue.