Last updated 18 August 2026

The PNG reference library (aka libpng) before 1.0.43, and 1.2.x before 1.2.35, as used in pngcrush and other applications, allows context-dependent attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted PNG file that triggers a free of an uninitialized pointer in (1) the pngreadpng function, (2) pCAL chunk handling, or (3) setup of 16-bit gamma tables.

An underflow read was found in pngcheckkeyword in pngwutil.c in libpng-1.2.54:

If the data of "key" is only ' ' (0x20), it will read a byte before the buffer in line 1288.

This issue impacts upstream versions 1.2.55, 1.0.65, 1.4.18, and 1.5.25 of libpng.

An attacker could possibly use this flaw to cause an out-of-bounds read by tricking an unsuspecting user into processing a specially crafted PNG image.

CVE assignment:

http://seclists.org/oss-sec/2015/q4/469

Upstream issue:

http://sourceforge.net/p/libpng/bugs/244/

Upstream patch:

http://sourceforge.net/p/libpng/code/ci/d9006f683c641793252d92254a75ae9b815b42ed/

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 (pnghandlepCAL), (2) sCAL (pnghandlesCAL), (3) tEXt (pngpushreadtEXt), (4) iTXt (pnghandleiTXt), and (5) ztXT (pnghandleztXt) chunking in PNG images, which trigger out-of-bounds read operations.

Off-by-one error in ICC profile chunk handling in the pngsetiCCP 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 pngpushreadzTXt 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 availin field value in a PNG image.