_TIFFCheckMalloc and _TIFFCheckRealloc in tif_aux.c in LibTIFF through 4.0.10 mishandle Integer Overflow checks because they rely on compiler behavior that is undefined by the applicable C standards. This can, for example, lead to an application crash.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.