Vulnerability hunting with Semmle QL: DOM XSS

In two previous blog posts ( part 1 and part 2), we talked about using Semmle QL in C and C++ codebases to find vulnerabilities such as integer overflow, path traversal, and those leading to memory corruption. In this post, we will explore applying Semmle QL to web security by hunting for one of­­­ the most common type of client-side vulnerabilities: DOM-based cross-site scripting (XSS).