A developer at a small startup company deployed some code for a new feature to...

Hard-coded credentials within code, especially when deployed in a public repository, are a common security vulnerability. If credentials such as passwords or API keys are embedded in the code, anyone with access to the repository can potentially use them to gain unauthorized access to databases or other sensitive resources. This is a likely cause of the data breach in the scenario described. References: CompTIA Security+ Guide to Network Security Fundamentals by Mark Ciampa.