Parse Server versions prior to 6.5.5 and 7.0.0 contain a critical vulnerability where calling an invalid Cloud Function or Cloud Job name can crash the server and potentially allow code injection, internal store manipulation, or remote code execution. The issue is addressed by input string sanitation in versions 6.5.5 and 7.0.0. Users should sanitize Cloud Function and Cloud Job names before they reach Parse Server as a workaround.