diff --git a/packages/block-library/src/footnotes/index.php b/packages/block-library/src/footnotes/index.php
index bd7734d7d02d1..444d13f4ec590 100644
--- a/packages/block-library/src/footnotes/index.php
+++ b/packages/block-library/src/footnotes/index.php
@@ -34,7 +34,7 @@ function render_block_core_footnotes( $attributes, $content, $block ) {
 
 	$footnotes = json_decode( $footnotes, true );
 
-	if ( count( $footnotes ) === 0 ) {
+	if ( ! is_array( $footnotes ) || count( $footnotes ) === 0 ) {
 		return '';
 	}