Cap Collectif vulnerable to insecure deserialization leading to remote code execution

Cap Collectif is an online decision making platform that integrates several tools. Before commit 812f2a7d271b76deab1175bdaf2be0b8102dd198, the `DebateAlternateArgumentsResolver` deserializes a `Cursor`, allowing any classes and which can be controlled by unauthenticated user. Exploitation of this vulnerability can lead to Remote Code Execution. The vulnerability is fixed in commit 812f2a7d271b76deab1175bdaf2be0b8102dd198.