CVE 2018-13818
** DISPUTED ** Twig before 2.4.4 allows Server-Side Template Injection (SSTI) via the search search_key parameter. NOTE: the vendor points out that Twig itself is not a web application and states that it is the responsibility of web applications using Twig to properly wrap input to it.
See the 
CVE page on Mitre.org
for more details.
