The qs package is a widely used npm library for parsing querystring parameters into objects, enabling advanced functionality such as creating nested objects within query strings. However, this functionality also brings risk, including the potential to overwrite properties in an object's prototype. A high-severity vulnerability was discovered and fixed by the package owner, with multiple versions of the library released to address the issue. To mitigate the vulnerability, users must update to a newer version of the qs package, which includes a more robust fix that prevents attackers from overriding the object's prototype properties.