diff --git a/wp-includes/formatting.php b/wp-includes/formatting.php
index b341ed7313..0f51a44b9c 100644
--- a/wp-includes/formatting.php
+++ b/wp-includes/formatting.php
@@ -216,7 +216,7 @@ function wptexturize( $text, $reset = false ) {
 
 	// Look for shortcodes and HTML elements.
 
-	preg_match_all( '@\[/?([^<>&/\[\]\x00-\x20]++)@', $text, $matches );
+	preg_match_all( '@\[/?([^<>&/\[\]\x00-\x20=]++)@', $text, $matches );
 	$tagnames = array_intersect( array_keys( $shortcode_tags ), $matches[1] );
 	$found_shortcodes = ! empty( $tagnames );
 	$shortcode_regex = $found_shortcodes ? _get_wptexturize_shortcode_regex( $tagnames ) : '';
diff --git a/wp-includes/shortcodes.php b/wp-includes/shortcodes.php
index 3967270922..132d63a5dc 100644
--- a/wp-includes/shortcodes.php
+++ b/wp-includes/shortcodes.php
@@ -95,9 +95,9 @@ function add_shortcode($tag, $func) {
 		return;
 	}
 
-	if ( 0 !== preg_match( '@[<>&/\[\]\x00-\x20]@', $tag ) ) {
-		/* translators: %s: shortcode name */
-		$message = sprintf( __( 'Invalid shortcode name: %s. Do not use spaces or reserved characters: & / < > [ ]' ), $tag );
+	if ( 0 !== preg_match( '@[<>&/\[\]\x00-\x20=]@', $tag ) ) {
+		/* translators: 1: shortcode name, 2: space separated list of reserved characters */
+		$message = sprintf( __( 'Invalid shortcode name: %1$s. Do not use spaces or reserved characters: %2$s' ), $tag, '& / < > [ ] =' );
 		_doing_it_wrong( __FUNCTION__, $message, '4.4.0' );
 		return;
 	}
@@ -210,7 +210,7 @@ function do_shortcode( $content, $ignore_html = false ) {
 		return $content;
 
 	// Find all registered tag names in $content.
-	preg_match_all( '@\[([^<>&/\[\]\x00-\x20]++)@', $content, $matches );
+	preg_match_all( '@\[([^<>&/\[\]\x00-\x20=]++)@', $content, $matches );
 	$tagnames = array_intersect( array_keys( $shortcode_tags ), $matches[1] );
 
 	if ( empty( $tagnames ) ) {
@@ -578,7 +578,7 @@ function strip_shortcodes( $content ) {
 		return $content;
 
 	// Find all registered tag names in $content.
-	preg_match_all( '@\[([^<>&/\[\]\x00-\x20]++)@', $content, $matches );
+	preg_match_all( '@\[([^<>&/\[\]\x00-\x20=]++)@', $content, $matches );
 	$tagnames = array_intersect( array_keys( $shortcode_tags ), $matches[1] );
 
 	if ( empty( $tagnames ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 6ede34a650..c9bd79eb1a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.5-alpha-36096';
+$wp_version = '4.5-alpha-36097';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.