diff --git a/wp-admin/js/site-health.js b/wp-admin/js/site-health.js
index 3314f41e1e..d91b75e90a 100644
--- a/wp-admin/js/site-health.js
+++ b/wp-admin/js/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/wp-admin/js/site-health.min.js b/wp-admin/js/site-health.min.js
index 1333d7a01f..18295a79da 100644
--- a/wp-admin/js/site-health.min.js
+++ b/wp-admin/js/site-health.min.js
@@ -1,2 +1,2 @@
 /*! This file is auto-generated */
-jQuery(document).ready(function(h){var a,t,s,c=wp.i18n.__,n=wp.i18n._n,o=wp.i18n.sprintf,i=new ClipboardJS(".site-health-copy-buttons .copy-button"),d=h(".health-check-body.health-check-debug-tab").length,l=h("#health-check-accordion-block-wp-paths-sizes");function r(e){var t,s,a=wp.template("health-check-issue"),i=h("#health-check-issues-"+e.status);SiteHealth.site_status.issues[e.status]++,s=SiteHealth.site_status.issues[e.status],void 0===e.test&&(e.test=e.status+s),"critical"===e.status?t=o(n("%s critical issue","%s critical issues",s),'<span class="issue-count">'+s+"</span>"):"recommended"===e.status?t=o(n("%s recommended improvement","%s recommended improvements",s),'<span class="issue-count">'+s+"</span>"):"good"===e.status&&(t=o(n("%s item with no issues detected","%s items with no issues detected",s),'<span class="issue-count">'+s+"</span>")),t&&h(".site-health-issue-count-title",i).html(t),h(".issues","#health-check-issues-"+e.status).append(a(e))}function u(){var e,t,s=h(".site-health-progress"),a=s.closest(".site-health-progress-wrapper"),i=h(".site-health-progress-label",a),n=h(".site-health-progress svg #bar"),o=parseInt(SiteHealth.site_status.issues.good,0)+parseInt(SiteHealth.site_status.issues.recommended,0)+1.5*parseInt(SiteHealth.site_status.issues.critical,0),l=.5*parseInt(SiteHealth.site_status.issues.recommended,0)+1.5*parseInt(SiteHealth.site_status.issues.critical,0),r=100-Math.ceil(l/o*100);0!==o?(a.removeClass("loading"),e=n.attr("r"),r<0&&(r=0),100<r&&(r=100),t=(100-r)/100*(Math.PI*(2*e)),n.css({strokeDashoffset:t}),parseInt(SiteHealth.site_status.issues.critical,0)<1&&h("#health-check-issues-critical").addClass("hidden"),parseInt(SiteHealth.site_status.issues.recommended,0)<1&&h("#health-check-issues-recommended").addClass("hidden"),80<=r&&0===parseInt(SiteHealth.site_status.issues.critical,0)?(a.addClass("green").removeClass("orange"),i.text(c("Good")),wp.a11y.speak(c("All site health tests have finished running. Your site is looking good, and the results are now available on the page."))):(a.addClass("orange").removeClass("green"),i.text(c("Should be improved")),wp.a11y.speak(c("All site health tests have finished running. There are items that should be addressed, and the results are now available on the page."))),d||(h.post(ajaxurl,{action:"health-check-site-status-result",_wpnonce:SiteHealth.nonce.site_status_result,counts:SiteHealth.site_status.issues}),100===r&&(h(".site-status-all-clear").removeClass("hide"),h(".site-status-has-issues").addClass("hide")))):s.addClass("hidden")}function p(e,t){var s;s={status:"recommended",label:c("A test is unavailable"),badge:{color:"red",label:c("Unavailable")},description:"<p>"+e+"</p><p>"+t+"</p>",actions:""},r(wp.hooks.applyFilters("site_status_test_result",s))}i.on("success",function(e){var t=h(e.trigger),s=h(".success",t.closest("div"));e.clearSelection(),t.focus(),clearTimeout(a),s.removeClass("hidden"),a=setTimeout(function(){s.addClass("hidden"),i.clipboardAction.fakeElem&&i.clipboardAction.removeFake&&i.clipboardAction.removeFake()},3e3),wp.a11y.speak(c("Site information has been copied to your clipboard."))}),h(".health-check-accordion").on("click",".health-check-accordion-trigger",function(){"true"===h(this).attr("aria-expanded")?(h(this).attr("aria-expanded","false"),h("#"+h(this).attr("aria-controls")).attr("hidden",!0)):(h(this).attr("aria-expanded","true"),h("#"+h(this).attr("aria-controls")).attr("hidden",!1))}),h(".site-health-view-passed").on("click",function(){var e=h("#health-check-issues-good");e.toggleClass("hidden"),h(this).attr("aria-expanded",!e.hasClass("hidden"))}),"undefined"==typeof SiteHealth||d||(0===SiteHealth.site_status.direct.length&&0===SiteHealth.site_status.async.length?u():SiteHealth.site_status.issues={good:0,recommended:0,critical:0},0<SiteHealth.site_status.direct.length&&h.each(SiteHealth.site_status.direct,function(){r(this)}),0<SiteHealth.site_status.async.length?function t(){var s=!0;1<=SiteHealth.site_status.async.length&&h.each(SiteHealth.site_status.async,function(){var e={action:"health-check-"+this.test.replace("_","-"),_wpnonce:SiteHealth.nonce.site_status};return!!this.completed||(s=!1,this.completed=!0,void 0!==this.has_rest&&this.has_rest?wp.apiRequest({url:this.test,headers:this.headers}).done(function(e){r(wp.hooks.applyFilters("site_status_test_result",e))}).fail(function(e){var t;t=void 0!==e.responseJSON&&void 0!==e.responseJSON.message?e.responseJSON.message:c("No details available"),p(this.url,t)}).always(function(){t()}):h.post(ajaxurl,e).done(function(e){r(wp.hooks.applyFilters("site_status_test_result",e.data))}).fail(function(e){var t;t=void 0!==e.responseJSON&&void 0!==e.responseJSON.message?e.responseJSON.message:c("No details available"),p(this.url,t)}).always(function(){t()}),!1)}),s&&u()}():u()),d&&(l.length?(t=(new Date).getTime(),s=window.setTimeout(function(){wp.a11y.speak(c("Please wait..."))},3e3),wp.apiRequest({path:"/wp-site-health/v1/directory-sizes"}).done(function(e){!function(i){var e=h("button.button.copy-button"),a=e.attr("data-clipboard-text");h.each(i,function(e,t){var s=t.debug||t.size;void 0!==s&&(a=a.replace(e+": loading...",e+": "+s))}),e.attr("data-clipboard-text",a),l.find("td[class]").each(function(e,t){var s=h(t),a=s.attr("class");i.hasOwnProperty(a)&&i[a].size&&s.text(i[a].size)})}(e||{})}).always(function(){var e=(new Date).getTime()-t;h(".health-check-wp-paths-sizes.spinner").css("visibility","hidden"),u(),3e3<e?(e=6e3<e?0:6500-e,window.setTimeout(function(){wp.a11y.speak(c("All site health tests have finished running."))},e)):window.clearTimeout(s),h(document).trigger("site-health-info-dirsizes-done")})):u())});
\ No newline at end of file
+jQuery(document).ready(function(c){var a,t,s,h=wp.i18n.__,n=wp.i18n._n,o=wp.i18n.sprintf,i=new ClipboardJS(".site-health-copy-buttons .copy-button"),d=c(".health-check-body.health-check-debug-tab").length,r=c("#health-check-accordion-block-wp-paths-sizes");function l(e){var t,s,a=wp.template("health-check-issue"),i=c("#health-check-issues-"+e.status);if(!function(e){var t,s,a,i,n={test:"string",label:"string",description:"string"},o=!0;if("object"!=typeof e)return!1;for(t in n)if("object"==typeof(s=n[t]))for(a in s)i=s[a],void 0!==e[t]&&void 0!==e[t][a]&&i===typeof e[t][a]||(o=!1);else void 0!==e[t]&&s===typeof e[t]||(o=!1);return o}(e))return!1;SiteHealth.site_status.issues[e.status]++,s=SiteHealth.site_status.issues[e.status],void 0===e.test&&(e.test=e.status+s),"critical"===e.status?t=o(n("%s critical issue","%s critical issues",s),'<span class="issue-count">'+s+"</span>"):"recommended"===e.status?t=o(n("%s recommended improvement","%s recommended improvements",s),'<span class="issue-count">'+s+"</span>"):"good"===e.status&&(t=o(n("%s item with no issues detected","%s items with no issues detected",s),'<span class="issue-count">'+s+"</span>")),t&&c(".site-health-issue-count-title",i).html(t),c(".issues","#health-check-issues-"+e.status).append(a(e))}function u(){var e,t,s=c(".site-health-progress"),a=s.closest(".site-health-progress-wrapper"),i=c(".site-health-progress-label",a),n=c(".site-health-progress svg #bar"),o=parseInt(SiteHealth.site_status.issues.good,0)+parseInt(SiteHealth.site_status.issues.recommended,0)+1.5*parseInt(SiteHealth.site_status.issues.critical,0),r=.5*parseInt(SiteHealth.site_status.issues.recommended,0)+1.5*parseInt(SiteHealth.site_status.issues.critical,0),l=100-Math.ceil(r/o*100);0!==o?(a.removeClass("loading"),e=n.attr("r"),l<0&&(l=0),100<l&&(l=100),t=(100-l)/100*(Math.PI*(2*e)),n.css({strokeDashoffset:t}),parseInt(SiteHealth.site_status.issues.critical,0)<1&&c("#health-check-issues-critical").addClass("hidden"),parseInt(SiteHealth.site_status.issues.recommended,0)<1&&c("#health-check-issues-recommended").addClass("hidden"),80<=l&&0===parseInt(SiteHealth.site_status.issues.critical,0)?(a.addClass("green").removeClass("orange"),i.text(h("Good")),wp.a11y.speak(h("All site health tests have finished running. Your site is looking good, and the results are now available on the page."))):(a.addClass("orange").removeClass("green"),i.text(h("Should be improved")),wp.a11y.speak(h("All site health tests have finished running. There are items that should be addressed, and the results are now available on the page."))),d||(c.post(ajaxurl,{action:"health-check-site-status-result",_wpnonce:SiteHealth.nonce.site_status_result,counts:SiteHealth.site_status.issues}),100===l&&(c(".site-status-all-clear").removeClass("hide"),c(".site-status-has-issues").addClass("hide")))):s.addClass("hidden")}function p(e,t){var s;s={status:"recommended",label:h("A test is unavailable"),badge:{color:"red",label:h("Unavailable")},description:"<p>"+e+"</p><p>"+t+"</p>",actions:""},l(wp.hooks.applyFilters("site_status_test_result",s))}i.on("success",function(e){var t=c(e.trigger),s=c(".success",t.closest("div"));e.clearSelection(),t.focus(),clearTimeout(a),s.removeClass("hidden"),a=setTimeout(function(){s.addClass("hidden"),i.clipboardAction.fakeElem&&i.clipboardAction.removeFake&&i.clipboardAction.removeFake()},3e3),wp.a11y.speak(h("Site information has been copied to your clipboard."))}),c(".health-check-accordion").on("click",".health-check-accordion-trigger",function(){"true"===c(this).attr("aria-expanded")?(c(this).attr("aria-expanded","false"),c("#"+c(this).attr("aria-controls")).attr("hidden",!0)):(c(this).attr("aria-expanded","true"),c("#"+c(this).attr("aria-controls")).attr("hidden",!1))}),c(".site-health-view-passed").on("click",function(){var e=c("#health-check-issues-good");e.toggleClass("hidden"),c(this).attr("aria-expanded",!e.hasClass("hidden"))}),"undefined"==typeof SiteHealth||d||(0===SiteHealth.site_status.direct.length&&0===SiteHealth.site_status.async.length?u():SiteHealth.site_status.issues={good:0,recommended:0,critical:0},0<SiteHealth.site_status.direct.length&&c.each(SiteHealth.site_status.direct,function(){l(this)}),0<SiteHealth.site_status.async.length?function t(){var s=!0;1<=SiteHealth.site_status.async.length&&c.each(SiteHealth.site_status.async,function(){var e={action:"health-check-"+this.test.replace("_","-"),_wpnonce:SiteHealth.nonce.site_status};return!!this.completed||(s=!1,this.completed=!0,void 0!==this.has_rest&&this.has_rest?wp.apiRequest({url:this.test,headers:this.headers}).done(function(e){l(wp.hooks.applyFilters("site_status_test_result",e))}).fail(function(e){var t;t=void 0!==e.responseJSON&&void 0!==e.responseJSON.message?e.responseJSON.message:h("No details available"),p(this.url,t)}).always(function(){t()}):c.post(ajaxurl,e).done(function(e){l(wp.hooks.applyFilters("site_status_test_result",e.data))}).fail(function(e){var t;t=void 0!==e.responseJSON&&void 0!==e.responseJSON.message?e.responseJSON.message:h("No details available"),p(this.url,t)}).always(function(){t()}),!1)}),s&&u()}():u()),d&&(r.length?(t=(new Date).getTime(),s=window.setTimeout(function(){wp.a11y.speak(h("Please wait..."))},3e3),wp.apiRequest({path:"/wp-site-health/v1/directory-sizes"}).done(function(e){!function(i){var e=c("button.button.copy-button"),a=e.attr("data-clipboard-text");c.each(i,function(e,t){var s=t.debug||t.size;void 0!==s&&(a=a.replace(e+": loading...",e+": "+s))}),e.attr("data-clipboard-text",a),r.find("td[class]").each(function(e,t){var s=c(t),a=s.attr("class");i.hasOwnProperty(a)&&i[a].size&&s.text(i[a].size)})}(e||{})}).always(function(){var e=(new Date).getTime()-t;c(".health-check-wp-paths-sizes.spinner").css("visibility","hidden"),u(),3e3<e?(e=6e3<e?0:6500-e,window.setTimeout(function(){wp.a11y.speak(h("All site health tests have finished running."))},e)):window.clearTimeout(s),c(document).trigger("site-health-info-dirsizes-done")})):u())});
\ No newline at end of file
diff --git a/wp-admin/site-health.php b/wp-admin/site-health.php
index 376ec80411..b7cc728ef6 100644
--- a/wp-admin/site-health.php
+++ b/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>
diff --git a/wp-includes/version.php b/wp-includes/version.php
index d72219dedf..8a3a8d781a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-beta3-49536';
+$wp_version = '5.6-beta3-49537';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.