This book constitutes the proceedings from the 38th Annual IFIP 11.3 Conference on Data and Applications Security and Privacy XXXVIII, DBSec 2024, held in San Jose, CA, USA, during July 15–17, 2024. The 14 full papers and 6 short papers presented were carefully reviewed and selected from 39 submissions. The papers are organized in the following topical sections: access control; crypto application; privacy; attack; ml attack, vulnerability; security user studies; and differential privacy.