CVE-2019-14874

In the __i2b function of the newlib libc library, all versions prior to 3.3.0 (see newlib/libc/stdlib/mprec.c), Balloc is used to allocate a big integer, however no check is performed to verify if the allocation succeeded or not. The access of _ x[0] will trigger a null pointer dereference bug in case of a memory allocation failure.