diff --git a/assets/js/hcaptcha-nf.js b/assets/js/hcaptcha-nf.js
index 9374cca2..0968c5d9 100644
--- a/assets/js/hcaptcha-nf.js
+++ b/assets/js/hcaptcha-nf.js
@@ -69,6 +69,10 @@ document.addEventListener( 'DOMContentLoaded', function() {
 	$.ajaxPrefilter( function( options ) {
 		const data = options.data ?? '';
 
+		if ( ! ( typeof data === 'string' || data instanceof String ) ) {
+			return;
+		}
+
 		if ( ! data.startsWith( 'action=nf_ajax_submit' ) ) {
 			return;
 		}
diff --git a/readme.txt b/readme.txt
index acc3fe35..122d22d8 100644
--- a/readme.txt
+++ b/readme.txt
@@ -561,6 +561,9 @@ Instructions for popular native integrations are below:
 
 == Changelog ==
 
+= 4.4.0 =
+* Fixed conflict with Ninja Forms Upload field.
+
 = 4.3.1 =
 * Added a live form in the Contact Form 7 admin form view.
 * Fixed warnings and deprecation messages in admin when Contact Form 7 is active.