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.
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.