Affected: Arm Ltd Arm Compiler for Embedded, Arm Ltd Arm Compiler for Embedded FuSa 6.16LTS, Arm Ltd Arm Compiler for Embedded FuSa 6.21, Arm Ltd Arm Compiler for Functional Safety 6.6, Arm Ltd CLang

When using Arm Cortex-M Security Extensions (CMSE), Secure stack contents can be leaked to Non-secure state via floating-point registers when a Secure to Non-secure function call is made that returns a floating-point value and when this is the first use of floating-point since entering Secure state. This allows an attacker to read a limited quantity of Secure stack contents with an impact on confidentiality. This issue is specific to code generated using LLVM-based compilers.