Index: src/wp-includes/embed.php
===================================================================
--- src/wp-includes/embed.php	(revision 53335)
+++ src/wp-includes/embed.php	(working copy)
@@ -1151,6 +1151,11 @@
 	if ( is_404() ) {
 		return;
 	}
+
+	$share_tab_wordpress_id   = uniqid( 'wp-embed-share-tab-wordpress-' );
+	$share_tab_html_id        = uniqid( 'wp-embed-share-tab-html-' );
+	$description_wordpress_id = uniqid( 'wp-embed-share-description-wordpress-' );
+	$description_html_id      = uniqid( 'wp-embed-share-description-html-' );
 	?>
 	<div class="wp-embed-share-dialog hidden" role="dialog" aria-label="<?php esc_attr_e( 'Sharing options' ); ?>">
 		<div class="wp-embed-share-dialog-content">
@@ -1157,23 +1162,23 @@
 			<div class="wp-embed-share-dialog-text">
 				<ul class="wp-embed-share-tabs" role="tablist">
 					<li class="wp-embed-share-tab-button wp-embed-share-tab-button-wordpress" role="presentation">
-						<button type="button" role="tab" aria-controls="wp-embed-share-tab-wordpress" aria-selected="true" tabindex="0"><?php esc_html_e( 'WordPress Embed' ); ?></button>
+						<button type="button" role="tab" aria-controls="<?php echo $share_tab_wordpress_id; ?>" aria-selected="true" tabindex="0"><?php esc_html_e( 'WordPress Embed' ); ?></button>
 					</li>
 					<li class="wp-embed-share-tab-button wp-embed-share-tab-button-html" role="presentation">
-						<button type="button" role="tab" aria-controls="wp-embed-share-tab-html" aria-selected="false" tabindex="-1"><?php esc_html_e( 'HTML Embed' ); ?></button>
+						<button type="button" role="tab" aria-controls="<?php echo $share_tab_html_id; ?>" aria-selected="false" tabindex="-1"><?php esc_html_e( 'HTML Embed' ); ?></button>
 					</li>
 				</ul>
-				<div id="wp-embed-share-tab-wordpress" class="wp-embed-share-tab" role="tabpanel" aria-hidden="false">
-					<input type="text" value="<?php the_permalink(); ?>" class="wp-embed-share-input" aria-describedby="wp-embed-share-description-wordpress" tabindex="0" readonly/>
+				<div id="<?php echo $share_tab_wordpress_id; ?>" class="wp-embed-share-tab" role="tabpanel" aria-hidden="false">
+					<input type="text" value="<?php the_permalink(); ?>" class="wp-embed-share-input" aria-label="<?php esc_attr_e( 'URL' ); ?>" aria-describedby="<?php echo $description_wordpress_id; ?>" tabindex="0" readonly/>
 
-					<p class="wp-embed-share-description" id="wp-embed-share-description-wordpress">
+					<p class="wp-embed-share-description" id="<?php echo $description_wordpress_id; ?>">
 						<?php _e( 'Copy and paste this URL into your WordPress site to embed' ); ?>
 					</p>
 				</div>
-				<div id="wp-embed-share-tab-html" class="wp-embed-share-tab" role="tabpanel" aria-hidden="true">
-					<textarea class="wp-embed-share-input" aria-describedby="wp-embed-share-description-html" tabindex="0" readonly><?php echo esc_textarea( get_post_embed_html( 600, 400 ) ); ?></textarea>
+				<div id="<?php echo $share_tab_html_id; ?>" class="wp-embed-share-tab" role="tabpanel" aria-hidden="true">
+					<textarea class="wp-embed-share-input" aria-label="<?php esc_attr_e( 'HTML' ); ?>" aria-describedby="<?php echo $description_html_id; ?>" tabindex="0" readonly><?php echo esc_textarea( get_post_embed_html( 600, 400 ) ); ?></textarea>
 
-					<p class="wp-embed-share-description" id="wp-embed-share-description-html">
+					<p class="wp-embed-share-description" id="<?php echo $description_html_id; ?>">
 						<?php _e( 'Copy and paste this code into your site to embed' ); ?>
 					</p>
 				</div>