The vulnerability lies in the /api/v3/search/categories endpoint, where the search parameter is not sanitized, leading to a SQL injection vulnerability. Without a specific patch, it's not possible to identify the exact code change. However, based on the application's structure, the search.categories function in src/controllers/search.js is the most probable location of the vulnerable code. This function would be responsible for taking the user-provided search term and using it in a database query. The lack of sanitization would make this function vulnerable. The confidence is medium because I cannot point to a specific line of code without a patch, but the location is highly likely based on the available information.