The most common vulnerabilities in Maven Central and npm are being tracked by Snyk's vulnerability database, which includes over 1 million open source packages from various ecosystems. The number of vulnerabilities published across these ecosystems reached an all-time high in 2017, with the most common types including Directory Traversal, Resources Downloaded over Insecure Protocol, Cross-Site Scripting (XSS), Denial of Service (DoS), Arbitrary Code Execution, and XSS attacks. These vulnerabilities can be exploited through various means, such as using relative directory paths to access sensitive data, intercepting connections to download resources securely, tricking browsers into executing malicious JavaScript code, saturating server resources, running malicious code on vulnerable servers, and filling server disks or memory with malicious code. The Snyk Vulnerability database provides a comprehensive view of vulnerabilities from these ecosystems, allowing developers to stay informed and protect their applications.