Integer overflow in the seek_to_and_unpack_pixeldata function in the psd.c plugin in Gimp 2.2.15 allows remote attackers to execute arbitrary code via a crafted PSD file that contains a large (1) width or (2) height value.
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.