The t2p_read_tiff_init function in tiff2pdf (tools/tiff2pdf.c) in LibTIFF 4.0.2 and earlier does not properly initialize the T2P context struct pointer in certain error conditions, which allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted TIFF image that triggers a heap-based buffer overflow.
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.