diff --git a/Algorithm/Optimization/GeneticOptimization.php b/Algorithm/Optimization/GeneticOptimization.php
index d048b2f6c..6c7fdccc1 100644
--- a/Algorithm/Optimization/GeneticOptimization.php
+++ b/Algorithm/Optimization/GeneticOptimization.php
@@ -104,7 +104,7 @@ class GeneticOptimization
     ) : array
     {
         $populationSize = \count($population);
-        $parameterCount = \count(\reset($population));
+        $parameterCount = $populationSize === 0 ? 0 : \count(\reset($population));
 
         // Genetic Algorithm Loop
         for ($generation = 0; $generation < $generations; ++$generation) {
diff --git a/Api/CreditRating/CreditSafe.php b/Api/CreditRating/CreditSafe.php
index 0361402d1..bac5a7ace 100644
--- a/Api/CreditRating/CreditSafe.php
+++ b/Api/CreditRating/CreditSafe.php
@@ -137,7 +137,7 @@ final class CreditSafe implements CreditRatingInterface
 
         $response = Rest::request($request);
 
-        return $response->get('companies') ?? ($response->get('matchedCompanies') ?? []);
+        return $response->getDataArray('companies') ?? ($response->getDataArray('matchedCompanies') ?? []);
     }
 
     /**
@@ -158,7 +158,7 @@ final class CreditSafe implements CreditRatingInterface
 
         $response = Rest::request($request);
 
-        return $response->get('report') ?? [];
+        return $response->getDataArray('report') ?? [];
     }
 
     /**
@@ -233,7 +233,7 @@ final class CreditSafe implements CreditRatingInterface
 
         $response = Rest::request($request);
 
-        return $response->get('orders') ?? [];
+        return $response->getDataArray('orders') ?? [];
     }
 
     /**
diff --git a/DataStorage/Session/JWT.php b/DataStorage/Session/JWT.php
index c1fd0ac2f..283651e03 100644
--- a/DataStorage/Session/JWT.php
+++ b/DataStorage/Session/JWT.php
@@ -37,7 +37,7 @@ final class JWT
      *
      * @param string                                                   $secret  Secret (at least 256 bit)
      * @param array{alg:string, typ:string}                            $header  Header
-     * @param array{sub:string, ?uid:string, ?name:string, iat:string} $payload Payload
+     * @param array{sub:string, uid?:string, name?:string, iat:string} $payload Payload
      *
      * @return string hmac(Header64 . Payload64, secret)
      *
@@ -45,8 +45,15 @@ final class JWT
      */
     private static function createSignature(string $secret, array $header, array $payload) : string
     {
-        $header64  = Base64Url::encode(\json_encode($header));
-        $payload64 = Base64Url::encode(\json_encode($payload));
+        $headerJson  = \json_encode($header);
+        $payloadJson = \json_encode($payload);
+
+        if (!\is_string($headerJson) || !\is_string($payloadJson)) {
+            return '';
+        }
+
+        $header64  = Base64Url::encode($headerJson);
+        $payload64 = Base64Url::encode($payloadJson);
 
         $algorithm = '';
         $algorithm = 'sha256';
@@ -59,7 +66,7 @@ final class JWT
      *
      * @param string                                                   $secret  Secret (at least 256 bit)
      * @param array{alg:string, typ:string}                            $header  Header
-     * @param array{sub:string, ?uid:string, ?name:string, iat:string} $payload Payload
+     * @param array{sub:string, uid?:string, name?:string, iat:string} $payload Payload
      *
      * @return string Header64 . Payload64 . hmac(Header64 . Payload64, secret)
      *
@@ -67,8 +74,16 @@ final class JWT
      */
     public static function createJWT(string $secret, array $header, array $payload) : string
     {
-        $header64  = Base64Url::encode(\json_encode($header));
-        $payload64 = Base64Url::encode(\json_encode($payload));
+        $headerJson  = \json_encode($header);
+        $payloadJson = \json_encode($payload);
+
+        if (!\is_string($headerJson) || !\is_string($payloadJson)) {
+            return '';
+        }
+
+        $header64  = Base64Url::encode($headerJson);
+        $payload64 = Base64Url::encode($payloadJson);
+
         $signature = self::createSignature($secret, $header, $payload);
 
         return $header64 . $payload64 . Base64Url::encode($signature);
@@ -87,7 +102,7 @@ final class JWT
     {
         $explode = \explode('.', $jwt);
 
-        if ($explode !== 3) {
+        if (\count($explode) !== 3) {
             return [];
         }
 
@@ -107,7 +122,7 @@ final class JWT
     {
         $explode = \explode('.', $jwt);
 
-        if ($explode !== 3) {
+        if (\count($explode) !== 3) {
             return [];
         }
 
@@ -128,7 +143,7 @@ final class JWT
     {
         $explode = \explode('.', $jwt);
 
-        if ($explode !== 3) {
+        if (\count($explode) !== 3) {
             return false;
         }
 
diff --git a/Message/Http/ImpressionStat.php b/Message/Http/ImpressionStat.php
index aeca5ccfe..15cd33a84 100644
--- a/Message/Http/ImpressionStat.php
+++ b/Message/Http/ImpressionStat.php
@@ -102,7 +102,7 @@ class ImpressionStat
     /**
      * Additional custom meta data to be stored
      *
-     * @var string
+     * @var array
      * @since 1.0.0
      */
     public array $meta = [];
diff --git a/Message/ResponseAbstract.php b/Message/ResponseAbstract.php
index 28537b59a..53ad70700 100755
--- a/Message/ResponseAbstract.php
+++ b/Message/ResponseAbstract.php
@@ -100,6 +100,26 @@ abstract class ResponseAbstract implements \JsonSerializable, MessageInterface
         return (string) $this->data[$key];
     }
 
+    /**
+     * Get data.
+     *
+     * @param string $key Data key
+     *
+     * @return ?array
+     *
+     * @since 1.0.0
+     */
+    public function getDataArray(string $key) : ?array
+    {
+        $key = \mb_strtolower($key);
+
+        if (($this->data[$key] ?? '') === '' || !\is_array($this->data[$key])) {
+            return null;
+        }
+
+        return $this->data[$key];
+    }
+
     /**
      * Get data.
      *
diff --git a/System/SystemUtils.php b/System/SystemUtils.php
index 7378a7246..0286cad5a 100755
--- a/System/SystemUtils.php
+++ b/System/SystemUtils.php
@@ -121,7 +121,12 @@ final class SystemUtils
                 return -1;
             }
 
-            $cpuUsage = $loadavg[0] * 100 / \exec('nproc');
+            $nproc = (int) \exec('nproc');
+            if ($nproc === 0) {
+                return 0;
+            }
+
+            $cpuUsage = $loadavg[0] * 100 / $nproc;
         }
 
         return (int) $cpuUsage;