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:
        WebCryptography.prototype.decryptString = function (key, ciphertext) {
            return __awaiter(this, void 0, void 0, function () {
                var abCiphertext, abIv, abPayload, abPlaintext;
                return __generator(this, function (_a) {
                    switch (_a.label) {
                        case 0:
                            abCiphertext = Buffer.from(ciphertext);
                            abIv = abCiphertext.slice(0, 16);
                            abPayload = abCiphertext.slice(16);
                            return [4 /*yield*/, crypto.subtle.decrypt({ name: 'AES-CBC', iv: abIv }, key, abPayload)];
                        case 1:
                            abPlaintext = _a.sent();
                            return [2 /*return*/, Buffer.from(abPlaintext).toString('utf8')];
                    }
                });
            });
        };