diff --git a/plugins/php-mime-mail-parser/Attachment.php b/plugins/php-mime-mail-parser/Attachment.php
index 1a731635..9b001a5b 100644
--- a/plugins/php-mime-mail-parser/Attachment.php
+++ b/plugins/php-mime-mail-parser/Attachment.php
@@ -241,7 +241,7 @@ class Attachment
             case Parser::ATTACHMENT_RANDOM_FILENAME:
                 $fileInfo = pathinfo($this->getFilename());
                 $extension  = empty($fileInfo['extension']) ? '' : '.'.$fileInfo['extension'];
-                $attachment_path = $attach_dir.uniqid().$extension;
+                $attachment_path = $attach_dir.bin2hex(random_bytes(16)).$extension;
                 break;
             case Parser::ATTACHMENT_DUPLICATE_THROW:
             case Parser::ATTACHMENT_DUPLICATE_SUFFIX:
diff --git a/plugins/php-mime-mail-parser/MiddlewareStack.php b/plugins/php-mime-mail-parser/MiddlewareStack.php
index 3ef6da93..ecab6445 100644
--- a/plugins/php-mime-mail-parser/MiddlewareStack.php
+++ b/plugins/php-mime-mail-parser/MiddlewareStack.php
@@ -29,7 +29,7 @@ class MiddlewareStack
      *
      * @param Middleware $middleware
      */
-    public function __construct(MiddleWareContracts $middleware = null)
+    public function __construct(?MiddleWareContracts $middleware = null)
     {
         $this->middleware = $middleware;
     }
diff --git a/plugins/php-mime-mail-parser/Parser.php b/plugins/php-mime-mail-parser/Parser.php
index 7f8a1de9..fcc4d7c6 100644
--- a/plugins/php-mime-mail-parser/Parser.php
+++ b/plugins/php-mime-mail-parser/Parser.php
@@ -74,7 +74,7 @@ class Parser
      *
      * @param CharsetManager|null $charset
      */
-    public function __construct(CharsetManager $charset = null)
+    public function __construct(?CharsetManager $charset = null)
     {
         if ($charset == null) {
             $charset = new Charset();
@@ -208,6 +208,11 @@ class Parser
      */
     protected function parse()
     {
+        if (!$this->resource) {
+            throw new Exception(
+                'MIME message cannot be parsed'
+            );
+        }
         $structure = mailparse_msg_get_structure($this->resource);
         $this->parts = [];
         foreach ($structure as $part_id) {
@@ -404,7 +409,7 @@ class Parser
             $body = empty($inline_parts) ? '' : $inline_parts[0];
         } else {
             throw new Exception(
-                'Invalid type specified for getMessageBody(). Expected: text, html or htmlEmbeded.'
+                'Invalid type specified for getMessageBody(). Expected: text, html or htmlEmbedded.'
             );
         }
 
@@ -450,7 +455,7 @@ class Parser
      *
      * @param string $name Header name (case-insensitive)
      *
-     * @return array
+     * @return array<int, array{'display': string, 'address': string, 'is_group': bool}>
      */
     public function getAddresses($name)
     {
@@ -464,9 +469,9 @@ class Parser
     }
 
     /**
-     * Returns the attachments contents in order of appearance
+     * Returns the inline parts contents (text or HTML)
      *
-     * @return Attachment[]
+     * @return string[] The decoded inline parts.
      */
     public function getInlineParts($type = 'text')
     {