Buffer overflow in the TIFF reader in gui/image/qtiffhandler.cpp in Qt 4.7.4 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via the TIFFTAG_SAMPLESPERPIXEL tag in a greyscale TIFF image with multiple samples per pixel.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.