The argument parser of the fetch command suffers a bug very
similiar to the partial command problem. Arguments like
"body[p", "binary[p" or "binary[p" will be wrongly detected
and the bufferposition can point outside of the allocated
buffer for the rest of the parsing process. When the parser
triggers the PARSE_PARTIAL macro after such a malformed
argument was received this can lead to a similiar one byte
memory corruption and allows remote code execution, when the
heap layout was successfully controlled by the attacker.