Fixes: out of array read
Fixes: poc.dat

Found-by: Bingchang, Liu @VARAS of IIE
Tested-by: bc L <l.bing.chang.bc@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 37138338)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>