You seem to be right that r65878 should block the "xsize = ysize = 0x8000" integer overflow.  I was testing on the python version with r60793, but not with r65878.  Note that the check added in r65878 should still cause crash on divide-by-zero for some files.

Attaching my test files. 1 is for excessive ZSIZE, 2 and 3 for the integer overflow, RLE and non-RLE code path, 4 and 5 for RLE decoding issues.  6 should trigger sigfpe in the r65878 check as noted above, but I've not really tested that one.