The two volume set LNCS 12972 + 12973 constitutes the proceedings of the 26^th European Symposium on Research in Computer Security, ESORICS 2021, which took place during October 4-8, 2021. The conference was originally planned to take place in Darmstadt, Germany, but changed to an online event due to the COVID-19 pandemic.

The 71 full papers presented in this book were carefully reviewed and selected from 351 submissions. They were organized in topical sections as follows:

Part I: network security; attacks; fuzzing; malware; user behavior and underground economy; blockchain; machine learning; automotive; anomaly detection;