Integer underflow in the png_check_keyword function in pngwutil.c in libpng 0.90 through 0.99, 1.0.x before 1.0.66, 1.1.x and 1.2.x before 1.2.56, 1.3.x and 1.4.x before 1.4.19, and 1.5.x before 1.5.26 allows remote attackers to have unspecified impact via a space character as a keyword in a PNG image, which triggers an out-of-bounds read.

The png_convert_to_rfc1123 function in png.c in libpng 1.0.x before 1.0.64, 1.2.x before 1.2.54, and 1.4.x before 1.4.17 allows remote attackers to obtain sensitive process memory information via crafted tIME chunk data in an image file, which triggers an out-of-bounds read.

The png_push_read_zTXt function in pngpread.c in libpng 1.0.x before 1.0.58, 1.2.x before 1.2.48, 1.4.x before 1.4.10, and 1.5.x before 1.5.10 allows remote attackers to cause a denial of service (out-of-bounds read) via a large avail_in field value in a PNG image.

The png_set_text_2 function in pngset.c in libpng 1.0.x before 1.0.59, 1.2.x before 1.2.49, 1.4.x before 1.4.11, and 1.5.x before 1.5.10 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a crafted text chunk in a PNG image file, which triggers a memory allocation failure that is not properly handled, leading to a heap-based buffer overflow.

Memory leak in the png_handle_tEXt function in pngrutil.c in libpng before 1.2.33 rc02 and 1.4.0 beta36 allows context-dependent attackers to cause a denial of service (memory exhaustion) via a crafted PNG file.

libpng 1.0.6 through 1.0.32, 1.2.0 through 1.2.26, and 1.4.0beta01 through 1.4.0beta19 allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via a PNG file with zero length "unknown" chunks, which trigger an access of uninitialized memory.

The sPLT chunk handling code (png_set_sPLT function in pngset.c) in libpng 1.0.6 through 1.2.12 uses a sizeof operator on the wrong data type, which allows context-dependent attackers to cause a denial of service (crash) via malformed sPLT chunks that trigger an out-of-bounds read.

Buffer overflow in the png_decompress_chunk function in pngrutil.c in libpng before 1.2.12 allows context-dependent attackers to cause a denial of service and possibly execute arbitrary code via unspecified vectors related to "chunk error processing," possibly involving the "chunk_name".

Heap-based buffer overflow in the alpha strip capability in libpng 1.2.7 allows context-dependent attackers to cause a denial of service (crash) when the png_do_strip_filler function is used to strip alpha channels out of the image.