Freeform 5.0.0 to before 5.10.16, a plugin for CraftCMS, contains an Server-side template injection (SSTI) vulnerability, resulting in arbitrary code injection for all users that have access to editing a form (submission title).
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.