diff --git a/api/upload_attachment.php b/api/upload_attachment.php
index 6fa4e48..481d99f 100644
--- a/api/upload_attachment.php
+++ b/api/upload_attachment.php
@@ -194,6 +194,23 @@ if ($file['size'] > $maxSize) {
     ResponseHelper::error('File size exceeds maximum allowed (' . AttachmentModel::formatFileSize($maxSize) . ')');
 }
 
+// Check per-ticket attachment count/storage quota — bounds an authenticated
+// low-privilege user slowly filling the uploads/ disk across many tickets,
+// which was previously bounded only by the request-rate limiter, not volume.
+$attachmentModel = new AttachmentModel($conn);
+$maxAttachments = $GLOBALS['config']['MAX_ATTACHMENTS_PER_TICKET'] ?? 50;
+if ($attachmentModel->getAttachmentCount($ticketId) >= $maxAttachments) {
+    ResponseHelper::error("This ticket already has the maximum of {$maxAttachments} attachments");
+}
+
+$maxTotalSize = $GLOBALS['config']['MAX_TOTAL_ATTACHMENT_SIZE_PER_TICKET'] ?? 104857600;
+if ($attachmentModel->getTotalSizeForTicket($ticketId) + $file['size'] > $maxTotalSize) {
+    ResponseHelper::error(
+        'This upload would exceed the ticket\'s total attachment size limit of '
+        . AttachmentModel::formatFileSize($maxTotalSize)
+    );
+}
+
 // Get MIME type
 $finfo = new finfo(FILEINFO_MIME_TYPE);
 $mimeType = $finfo->file($file['tmp_name']);
@@ -265,7 +282,6 @@ if (empty($originalFilename)) {
 
 // Save to database
 try {
-    $attachmentModel = new AttachmentModel($conn);
     $attachmentId = $attachmentModel->addAttachment(
         $ticketId,
         $uniqueFilename,
diff --git a/config/config.php b/config/config.php
index 3ffb242..80ab44e 100644
--- a/config/config.php
+++ b/config/config.php
@@ -115,6 +115,8 @@ $GLOBALS['config'] = [
 
     // File upload settings
     'MAX_UPLOAD_SIZE' => 10485760, // 10MB in bytes
+    'MAX_ATTACHMENTS_PER_TICKET' => 50,
+    'MAX_TOTAL_ATTACHMENT_SIZE_PER_TICKET' => 104857600, // 100MB in bytes
     'ALLOWED_FILE_TYPES' => [
         'image/jpeg',
         'image/png',