diff --git a/wp-includes/class-wp-theme-json.php b/wp-includes/class-wp-theme-json.php
index 735163553e..174f50c8f0 100644
--- a/wp-includes/class-wp-theme-json.php
+++ b/wp-includes/class-wp-theme-json.php
@@ -589,8 +589,15 @@ class WP_Theme_JSON {
 		$this->theme_json    = WP_Theme_JSON_Schema::migrate( $theme_json );
 		$valid_block_names   = array_keys( static::get_blocks_metadata() );
 		$valid_element_names = array_keys( static::ELEMENTS );
-		$theme_json          = static::sanitize( $this->theme_json, $valid_block_names, $valid_element_names );
-		$this->theme_json    = static::maybe_opt_in_into_settings( $theme_json );
+		$valid_variations    = array();
+		foreach ( self::get_blocks_metadata() as $block_name => $block_meta ) {
+			if ( ! isset( $block_meta['styleVariations'] ) ) {
+				continue;
+			}
+			$valid_variations[ $block_name ] = array_keys( $block_meta['styleVariations'] );
+		}
+		$theme_json       = static::sanitize( $this->theme_json, $valid_block_names, $valid_element_names, $valid_variations );
+		$this->theme_json = static::maybe_opt_in_into_settings( $theme_json );
 
 		// Internally, presets are keyed by origin.
 		$nodes = static::get_setting_nodes( $this->theme_json );
@@ -668,9 +675,10 @@ class WP_Theme_JSON {
 	 * @param array $input               Structure to sanitize.
 	 * @param array $valid_block_names   List of valid block names.
 	 * @param array $valid_element_names List of valid element names.
+	 * @param array $valid_variations List of valid variations per block.
 	 * @return array The sanitized output.
 	 */
-	protected static function sanitize( $input, $valid_block_names, $valid_element_names ) {
+	protected static function sanitize( $input, $valid_block_names, $valid_element_names, $valid_variations ) {
 
 		$output = array();
 
@@ -728,9 +736,13 @@ class WP_Theme_JSON {
 			$style_variation_names = array();
 			if (
 				! empty( $input['styles']['blocks'][ $block ]['variations'] ) &&
-				is_array( $input['styles']['blocks'][ $block ]['variations'] )
+				is_array( $input['styles']['blocks'][ $block ]['variations'] ) &&
+				isset( $valid_variations[ $block ] )
 			) {
-				$style_variation_names = array_keys( $input['styles']['blocks'][ $block ]['variations'] );
+				$style_variation_names = array_intersect(
+					array_keys( $input['styles']['blocks'][ $block ]['variations'] ),
+					$valid_variations[ $block ]
+				);
 			}
 
 			$schema_styles_variations = array();
@@ -2852,8 +2864,15 @@ class WP_Theme_JSON {
 
 		$valid_block_names   = array_keys( static::get_blocks_metadata() );
 		$valid_element_names = array_keys( static::ELEMENTS );
+		$valid_variations    = array();
+		foreach ( self::get_blocks_metadata() as $block_name => $block_meta ) {
+			if ( ! isset( $block_meta['styleVariations'] ) ) {
+				continue;
+			}
+			$valid_variations[ $block_name ] = array_keys( $block_meta['styleVariations'] );
+		}
 
-		$theme_json = static::sanitize( $theme_json, $valid_block_names, $valid_element_names );
+		$theme_json = static::sanitize( $theme_json, $valid_block_names, $valid_element_names, $valid_variations );
 
 		$blocks_metadata = static::get_blocks_metadata();
 		$style_nodes     = static::get_style_nodes( $theme_json, $blocks_metadata );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 0bc14a6a62..c935a10807 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.3-alpha-55911';
+$wp_version = '6.3-alpha-55912';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.