Raptor2 versions prior to 2.0.15-22.oe2403sp1 contain a heap-based buffer overflow vulnerability in the function raptor_new_term_from_counted_literal(). This flaw arises from truncating the length of language tags to an unsigned char, allowing attackers to supply RDF documents with language tags of 256 bytes or longer. Exploitation can lead to heap memory corruption, application crashes, and potentially arbitrary code execution. A fix is available in version 2.0.15-22.oe2403sp1.