diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index a31e77b00e26c..c6c6a2cefeb6c 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -5879,7 +5879,7 @@ function _wp_add_additional_image_sizes() {
 function wp_show_heic_upload_error( $plupload_settings ) {
 	// Check if HEIC images can be edited.
 	if ( ! wp_image_editor_supports( array( 'mime_type' => 'image/heic' ) ) ) {
-		$plupload_init['heic_upload_error'] = true;
+		$plupload_settings['heic_upload_error'] = true;
 	}
 	return $plupload_settings;
 }
diff --git a/tests/phpunit/tests/media/wpShowHeicUploadError.php b/tests/phpunit/tests/media/wpShowHeicUploadError.php
new file mode 100644
index 0000000000000..468a636e2cd07
--- /dev/null
+++ b/tests/phpunit/tests/media/wpShowHeicUploadError.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * Tests for the `wp_show_heic_upload_error()` function.
+ *
+ * @group media
+ * @covers ::wp_show_heic_upload_error
+ */
+class Tests_Media_wpShowHeicUploadError extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 65802
+	 */
+	public function test_adds_error_flag_to_the_given_settings_when_heic_is_not_editable() {
+		add_filter( 'wp_image_editors', '__return_empty_array' );
+
+		$this->assertSame(
+			array(
+				'existing'          => 'value',
+				'heic_upload_error' => true,
+			),
+			wp_show_heic_upload_error( array( 'existing' => 'value' ) )
+		);
+	}
+}