sift (sift.js) 17.1.3 enumerates query keys with for...in, which walks the object prototype chain, and dispatches any matched operator key including $where. The $where operation compiles a string value into a function using new Function unless CSPENABLED is set (not set by default). As a result, if a prototype-pollution primitive elsewhere in the process sets Object.prototype.$where to a malicious string, even benign filter calls such as sift({}) execute arbitrary JavaScript. Additionally, passing an untrusted query object containing a string $where directly to sift results in code execution under the default configuration.

Cross-site scripting (XSS) vulnerability in search.cgi in Sift Unity allows remote attackers to inject arbitrary web script or HTML via the qt parameter. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.