Software vulnerabilities are security-related software bugs. Direct disclosure refers to a practice that is widely used for communicating the confidential information about vulnerabilities between two parties, vulnerability discoverers and software producers. Building on software vulnerability life cycle analysis, this empirical paper observes the qualitative and quantitative characteristics of direct disclosure practices, focusing particularly on the historical problem related to producers’ reluctance to participate in the practices. According to the results, the problem was still present in the 2000s and early 2010s—and likely is still present today. By presenting this empirical result about the under researched phenomenon of direct disclosure of software vulnerabilities, the paper contributes to the research domain of vulnerability life cycle modeling in general and the subdomain of empirical vulnerability disclosure research in particular.