Any project that parses untrusted Protocol Buffers dataย containing an arbitrary number of nested groups / series of SGROUPย tags can corrupted by exceeding the stack limit i.e. StackOverflow. Parsing nested groups as unknown fields with DiscardUnknownFieldsParser or Java Protobuf Lite parser, or against Protobuf map fields, creates unbounded recursions that can be abused by an attacker.