zydis -- heap buffer overflow

Zyantific reports:

Zydis users of versions v3.2.0 and older
that use the string functions provided in zycore in order to
append untrusted user data to the formatter buffer within
their custom formatter hooks can run into heap buffer
overflows. Older versions of Zydis failed to properly
initialize the string object within the formatter buffer,
forgetting to initialize a few fields, leaving their value
to chance. This could then in turn cause zycore functions
like ZyanStringAppend to make incorrect calculations for the
new target size, resulting in heap memory corruption.