PHP-Memcached v2.2.0 and below contains an improper NULL termination which allows attackers to execute CLRF injection. Note: Third parties have disputed this as not affecting PHP-Memcached directly.
https://xhzeem.me/posts/Php5-memcached-Injection-Bypass/read/
https://github.com/php-memcached-dev/php-memcached/issues/519