diff --git a/src/js/_enqueues/admin/site-health.js b/src/js/_enqueues/admin/site-health.js
index 3314f41e1e..d91b75e90a 100644
--- a/src/js/_enqueues/admin/site-health.js
+++ b/src/js/_enqueues/admin/site-health.js
@@ -65,6 +65,57 @@ jQuery( document ).ready( function( $ ) {
 		$( this ).attr( 'aria-expanded', ! goodIssuesWrapper.hasClass( 'hidden' ) );
 	} );
 
+	/**
+	 * Validates the Site Health test result format.
+	 *
+	 * @since 5.6.0
+	 *
+	 * @param {Object} issue
+	 *
+	 * @return {boolean}
+	 */
+	function validateIssueData( issue ) {
+		// Expected minimum format of a valid SiteHealth test response.
+		var minimumExpected = {
+				test: 'string',
+				label: 'string',
+				description: 'string'
+			},
+			passed = true,
+			key, value, subKey, subValue;
+
+		// If the issue passed is not an object, return a `false` state early.
+		if ( 'object' !== typeof( issue ) ) {
+			return false;
+		}
+
+		// Loop over expected data and match the data types.
+		for ( key in minimumExpected ) {
+			value = minimumExpected[ key ];
+
+			if ( 'object' === typeof( value ) ) {
+				for ( subKey in value ) {
+					subValue = value[ subKey ];
+
+					if ( 'undefined' === typeof( issue[ key ] ) ||
+						'undefined' === typeof( issue[ key ][ subKey ] ) ||
+						subValue !== typeof( issue[ key ][ subKey ] )
+					) {
+						passed = false;
+					}
+				}
+			} else {
+				if ( 'undefined' === typeof( issue[ key ] ) ||
+					value !== typeof( issue[ key ] )
+				) {
+					passed = false;
+				}
+			}
+		}
+
+		return passed;
+	}
+
 	/**
 	 * Appends a new issue to the issue list.
 	 *
@@ -78,6 +129,14 @@ jQuery( document ).ready( function( $ ) {
 			heading,
 			count;
 
+		/*
+		 * Validate the issue data format before using it.
+		 * If the output is invalid, discard it.
+		 */
+		if ( ! validateIssueData( issue ) ) {
+			return false;
+		}
+
 		SiteHealth.site_status.issues[ issue.status ]++;
 
 		count = SiteHealth.site_status.issues[ issue.status ];
diff --git a/src/wp-admin/site-health.php b/src/wp-admin/site-health.php
index 376ec80411..b7cc728ef6 100644
--- a/src/wp-admin/site-health.php
+++ b/src/wp-admin/site-health.php
@@ -144,7 +144,9 @@ require_once ABSPATH . 'wp-admin/admin-header.php';
 	<h4 class="health-check-accordion-heading">
 		<button aria-expanded="false" class="health-check-accordion-trigger" aria-controls="health-check-accordion-block-{{ data.test }}" type="button">
 			<span class="title">{{ data.label }}</span>
-			<span class="badge {{ data.badge.color }}">{{ data.badge.label }}</span>
+			<# if ( data.badge ) { #>
+				<span class="badge {{ data.badge.color }}">{{ data.badge.label }}</span>
+			<# } #>
 			<span class="icon"></span>
 		</button>
 	</h4>