Our web security analysis aims at quantifying the number of domains hosting web applications that can be exploited by taking over the vulnerable domains discovered by RDScan. In particular, for every apex domain with at least one vulnerable subdomain, we selected from the CommonCrawl dataset [¹⁹ Common Crawl. Host- and domain-level webgraphs feb/mar/may 2020. https://commoncrawl.org/2020/06/host-and-domain-level-web-graphs-febmarmay-2020/, 2020.] the list of 200 most popular related-domains according to the Pagerank score [11]. From the homepage of these domains,we extracted the same-origin links that appear in the HTML code.