Language: JavaScript
Label: vulnerable
CWE: CWE-331 \u2014 Insufficient Entropy
The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.

Code:
function prepareMessagePayload(modules, messagePayload) {
    var crypto = modules.crypto, config = modules.config;
    var stringifiedPayload = JSON.stringify(messagePayload);
    if (config.cipherKey) {
        stringifiedPayload = crypto.encrypt(stringifiedPayload);
        stringifiedPayload = JSON.stringify(stringifiedPayload);
    }
    return stringifiedPayload;
}