SPIP 2.x before 2.1.19, 3.0.x before 3.0.22, and 3.1.x before 3.1.1 allows remote attackers to execute arbitrary PHP code by adding content, related to the filtrer_entites function.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2016-4205
https://core.spip.net/projects/spip/repository/revisions/22911