diff --git a/wp-includes/html-api/class-wp-html-open-elements.php b/wp-includes/html-api/class-wp-html-open-elements.php
index 5ce1f8feb5..cb913853f0 100644
--- a/wp-includes/html-api/class-wp-html-open-elements.php
+++ b/wp-includes/html-api/class-wp-html-open-elements.php
@@ -530,31 +530,31 @@ class WP_HTML_Open_Elements {
 	}
 
 	/**
-	 * Pops nodes off of the stack of open elements until one with the given tag name has been popped.
+	 * Pops nodes off of the stack of open elements until an HTML tag with the given name has been popped.
 	 *
 	 * @since 6.4.0
 	 *
 	 * @see WP_HTML_Open_Elements::pop
 	 *
-	 * @param string $tag_name Name of tag that needs to be popped off of the stack of open elements.
+	 * @param string $html_tag_name Name of tag that needs to be popped off of the stack of open elements.
 	 * @return bool Whether a tag of the given name was found and popped off of the stack of open elements.
 	 */
-	public function pop_until( string $tag_name ): bool {
+	public function pop_until( string $html_tag_name ): bool {
 		foreach ( $this->walk_up() as $item ) {
-			if ( 'context-node' === $item->bookmark_name ) {
-				return true;
-			}
-
 			$this->pop();
 
+			if ( 'html' !== $item->namespace ) {
+				continue;
+			}
+
 			if (
-				'(internal: H1 through H6 - do not use)' === $tag_name &&
+				'(internal: H1 through H6 - do not use)' === $html_tag_name &&
 				in_array( $item->node_name, array( 'H1', 'H2', 'H3', 'H4', 'H5', 'H6' ), true )
 			) {
 				return true;
 			}
 
-			if ( $tag_name === $item->node_name ) {
+			if ( $html_tag_name === $item->node_name ) {
 				return true;
 			}
 		}
diff --git a/wp-includes/html-api/class-wp-html-processor.php b/wp-includes/html-api/class-wp-html-processor.php
index 55b9061368..cb581fac39 100644
--- a/wp-includes/html-api/class-wp-html-processor.php
+++ b/wp-includes/html-api/class-wp-html-processor.php
@@ -5428,6 +5428,11 @@ class WP_HTML_Processor extends WP_HTML_Tag_Processor {
 				}
 			}
 
+			// All of the following rules are for matching HTML elements.
+			if ( 'html' !== $node->namespace ) {
+				continue;
+			}
+
 			switch ( $node->node_name ) {
 				/*
 				 * > 4. If node is a `select` element, run these substeps:
@@ -5443,6 +5448,10 @@ class WP_HTML_Processor extends WP_HTML_Tag_Processor {
 				case 'SELECT':
 					if ( ! $last ) {
 						foreach ( $this->state->stack_of_open_elements->walk_up( $node ) as $ancestor ) {
+							if ( 'html' !== $ancestor->namespace ) {
+								continue;
+							}
+
 							switch ( $ancestor->node_name ) {
 								/*
 								 * > 5. If _ancestor_ is a `template` node, jump to the step below
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 5e202be177..fc15073f1d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-alpha-58988';
+$wp_version = '6.7-alpha-58992';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.