Index: wp-activate.php
===================================================================
--- wp-activate.php	(revision 55900)
+++ wp-activate.php	(working copy)
@@ -128,7 +128,7 @@
 	<?php if ( ! $key ) { ?>
 
 		<h2><?php _e( 'Activation Key Required' ); ?></h2>
-		<form name="activateform" id="activateform" method="post" action="<?php echo network_site_url( $blog_details->path . 'wp-activate.php' ); ?>">
+		<form name="activateform" id="activateform" method="post" action="<?php echo esc_url( network_site_url( $blog_details->path . 'wp-activate.php' ) ); ?>">
 			<p>
 				<label for="key"><?php _e( 'Activation Key:' ); ?></label>
 				<br /><input type="text" name="key" id="key" value="" size="50" autofocus="autofocus" />
Index: wp-includes/theme-compat/footer.php
===================================================================
--- wp-includes/theme-compat/footer.php	(revision 55900)
+++ wp-includes/theme-compat/footer.php	(working copy)
@@ -23,9 +23,10 @@
 		<?php
 		printf(
 			/* translators: 1: Site name, 2: WordPress */
-			__( '%1$s is proudly powered by %2$s' ),
+			__( '%1$s is proudly powered by <a href="%2$s">%3$s</a>' ),
 			get_bloginfo( 'name' ),
-			'<a href="https://wordpress.org/">WordPress</a>'
+			esc_url( __( 'https://wordpress.org/' ) ),
+			esc_html__( 'WordPress' )
 		);
 		?>
 	</p>