diff --git a/projects/packages/jetpack-mu-wpcom/changelog/fix-clean_up_loose_hostname_matches b/projects/packages/jetpack-mu-wpcom/changelog/fix-clean_up_loose_hostname_matches
new file mode 100644
index 000000000000..838cb4533425
--- /dev/null
+++ b/projects/packages/jetpack-mu-wpcom/changelog/fix-clean_up_loose_hostname_matches
@@ -0,0 +1,5 @@
+Significance: patch
+Type: fixed
+Comment: Clean up loose hostname matches.
+
+
diff --git a/projects/packages/jetpack-mu-wpcom/src/features/wpcom-themes/js/theme-actions.js b/projects/packages/jetpack-mu-wpcom/src/features/wpcom-themes/js/theme-actions.js
index afe6d41ef7b5..70390fddce2b 100644
--- a/projects/packages/jetpack-mu-wpcom/src/features/wpcom-themes/js/theme-actions.js
+++ b/projects/packages/jetpack-mu-wpcom/src/features/wpcom-themes/js/theme-actions.js
@@ -10,7 +10,7 @@ const wpcomThemesRemoveWpcomActions = () => {
 			for ( const node of mutation.addedNodes ) {
 				const themeActions = node.querySelector( '.theme-actions .active-theme' );
 				for ( const action of themeActions?.children ?? [] ) {
-					if ( action.getAttribute( 'href' )?.includes( 'https://wordpress.com' ) ) {
+					if ( action.getAttribute( 'href' )?.startsWith( 'https://wordpress.com/' ) ) {
 						themeActions.removeChild( action );
 					}
 				}
diff --git a/projects/packages/masterbar/changelog/fix-clean_up_loose_hostname_matches b/projects/packages/masterbar/changelog/fix-clean_up_loose_hostname_matches
new file mode 100644
index 000000000000..838cb4533425
--- /dev/null
+++ b/projects/packages/masterbar/changelog/fix-clean_up_loose_hostname_matches
@@ -0,0 +1,5 @@
+Significance: patch
+Type: fixed
+Comment: Clean up loose hostname matches.
+
+
diff --git a/projects/packages/masterbar/src/nudges/additional-css/additional-css.js b/projects/packages/masterbar/src/nudges/additional-css/additional-css.js
index 4a8a88bc4438..5ab7667ccc0d 100644
--- a/projects/packages/masterbar/src/nudges/additional-css/additional-css.js
+++ b/projects/packages/masterbar/src/nudges/additional-css/additional-css.js
@@ -20,7 +20,7 @@ import './additional-css.css';
 				// Get destination.
 				const destination = this.getAttribute( 'data-navigate-to-page' );
 
-				if ( ! destination ) {
+				if ( ! destination?.startsWith( '/' ) ) {
 					return;
 				}
 
diff --git a/projects/plugins/boost/app/modules/optimizations/image-cdn/src/srcset.ts b/projects/plugins/boost/app/modules/optimizations/image-cdn/src/srcset.ts
index 77e6ca350ad1..b77ad648e52c 100644
--- a/projects/plugins/boost/app/modules/optimizations/image-cdn/src/srcset.ts
+++ b/projects/plugins/boost/app/modules/optimizations/image-cdn/src/srcset.ts
@@ -86,12 +86,19 @@ export function dynamicSrcset( img: HTMLImageElement ) {
 		! img.getAttribute( 'width' ) ||
 		! img.getAttribute( 'height' ) ||
 		! img.srcset ||
-		! img.src ||
-		! img.src.includes( '.wp.com' )
+		! img.src
 	) {
 		return;
 	}
 
+	try {
+		if ( ! new URL( img.src ).hostname.endsWith( '.wp.com' ) ) {
+			return;
+		}
+	} catch {
+		return;
+	}
+
 	const rect = img.getBoundingClientRect();
 	const targetSize = calculateTargetSize( rect );
 
diff --git a/projects/plugins/boost/changelog/fix-clean_up_loose_hostname_matches b/projects/plugins/boost/changelog/fix-clean_up_loose_hostname_matches
new file mode 100644
index 000000000000..838cb4533425
--- /dev/null
+++ b/projects/plugins/boost/changelog/fix-clean_up_loose_hostname_matches
@@ -0,0 +1,5 @@
+Significance: patch
+Type: fixed
+Comment: Clean up loose hostname matches.
+
+