The png_set_text_2 function in libpng 0.71 before 1.0.67, 1.2.x before 1.2.57, 1.4.x before 1.4.20, 1.5.x before 1.5.28, and 1.6.x before 1.6.27 allows context-dependent attackers to cause a NULL pointer dereference vectors involving loading a text chunk into a png structure, removing the text, and then adding another text chunk to the structure.

libpng before 1.2.37 does not properly parse 1-bit interlaced images with width values that are not divisible by 8, which causes libpng to include uninitialized bits in certain rows of a PNG file and might allow remote attackers to read portions of sensitive memory via "out-of-bounds pixels" in the file.