Avoid uninitialized memory
Avoid uninitialized memory

As reported by https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=16856

tbeu/matio,tbeu/matio,MaartenBent/matio,tbeu/matio,tbeu/matio,MaartenBent/matio,MaartenBent/matio,MaartenBent/matio