Security and reliability problems in edge devices can become the Achilles\' heel for their massive use in Internet of Things (IoT) systems. While most works address security by implementing lightweight cryptographic algorithms, this paper is the first to assess the soft error reliability of lightweight cryptographic algorithms targeting IoT edge devices. This paper performs soft error analysis for ten lightweight cryptographic algorithms considering two compilers and running on top of an IoT-ready commercial processor model (i.e. Arm Cortex-M7). From the ten lightweight cryptographic algorithms, IDEA shows the best trade-off between performance and reliability.