Multiple buffer overflows in the (1) png_set_PLTE and (2) png_get_PLTE functions in libpng before 1.0.64, 1.1.x and 1.2.x before 1.2.54, 1.3.x and 1.4.x before 1.4.17, 1.5.x before 1.5.24, and 1.6.x before 1.6.19 allow remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a small bit-depth value in an IHDR (aka image header) chunk in a PNG image.
The png_do_expand_palette function in libpng before 1.6.8 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via (1) a PLTE chunk of zero bytes or (2) a NULL palette, related to pngrtran.c and pngset.c.