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.

Off-by-one error in ICC profile chunk handling in the png_set_iCCP function in pngset.c in libpng before 1.2.22 beta1 allows remote attackers to cause a denial of service (crash) via a crafted PNG image, due to an incorrect fix for CVE-2007-5266.

Certain chunk handlers in libpng before 1.0.29 and 1.2.x before 1.2.21 allow remote attackers to cause a denial of service (crash) via crafted (1) pCAL (png_handle_pCAL), (2) sCAL (png_handle_sCAL), (3) tEXt (png_push_read_tEXt), (4) iTXt (png_handle_iTXt), and (5) ztXT (png_handle_ztXt) chunking in PNG images, which trigger out-of-bounds read operations.

pngrtran.c in libpng before 1.0.29 and 1.2.x before 1.2.21 use (1) logical instead of bitwise operations and (2) incorrect comparisons, which might allow remote attackers to cause a denial of service (crash) via a crafted PNG image.

Off-by-one error in ICC profile chunk handling in the png_set_iCCP function in pngset.c in libpng before 1.0.29 beta1 and 1.2.x before 1.2.21 beta1 allows remote attackers to cause a denial of service (crash) via a crafted PNG image that prevents a name field from being NULL terminated.

The Portable Network Graphics library (libpng) 1.0.15 and earlier allows attackers to cause a denial of service (crash) via a malformed PNG image file that triggers an error that causes an out-of-bounds read when creating the error message.