libpng before 1.6.32 does not properly check the length of chunks against the user limit.

png_image_free in png.c in libpng 1.6.x before 1.6.37 has a use-after-free because png_image_free_function is called under png_safe_execute.

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.

Unspecified vulnerability in libpng before 1.6.20, as used in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-07-01, allows attackers to gain privileges via a crafted application, as demonstrated by obtaining Signature or SignatureOrSystem access, aka internal bug 23265085.

Buffer overflow in the png_set_PLTE function in libpng before 1.0.65, 1.1.x and 1.2.x before 1.2.55, 1.3.x, 1.4.x before 1.4.18, 1.5.x before 1.5.25, and 1.6.x before 1.6.20 allows 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. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-8126.