This paper studies nonadaptive Mastermind algorithms for attacking the privacy of string and vector databases like DNA strings, movie ratings, and social network data. The algorithms can take advantage of minimal privacy leaks, like whether two people share any genetic mutations or common friends. The attacks are analyzed theoretically and experimentally on genomic, recommendation, and social network data. By exploiting the sparse nature of real-world databases and modulating query sparsity, the paper shows relatively few nonadaptive queries are needed to recover a large portion of each database.