The latest version of WordPress adding rel='noreferrer noopener' tag automatically, if you set the link to open in a new tab. That means if you use target='_blank' tag then the rel='noreferrer noopener' tag is automatically added, and there is no way to remove it, if you remove it from html mode in editor the tag will automatically back after the post update.

The thing is rel='noopener' tag will be helpful to prevent the site attack, but we need to remove the rel='noreferrer' tag.

Some themes might already have the tag disable script integrated, so you should check first if there is tag applied in your link source.

Add the following codes at the end of your WordPress theme’s functions.php file to change the tag.

//This code removes noreferrer from your new or updated posts
add_filter( 'wp_targeted_link_rel', 'my_targeted_link_rel_remove_noreferrer',999);
function my_targeted_link_rel_remove_noreferrer( $rel_values ) {
return preg_replace( '/noreferrer\s*/i', 'nofollow', $rel_values );

Then remove the existing tag from your site posts.

Enjoy !