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/

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. Prior to 1.6.55, an out-of-bounds read vulnerability exists in the pngsetquantize() API function. When the function is called with no histogram and the number of colors in the palette is more than twice the maximum supported by the user's display, certain palettes will cause the function to enter into an infinite loop that reads past the end of an internal heap-allocated buffer. The images that trigger this vulnerability are valid per the PNG specification. This vulnerability is fixed in 1.6.55.

LIBPNG has an integer truncation causing heap buffer over-read in pngimagewrite

Last updated 18 August 2026

Last updated 18 August 2026

Buffer overflow in libpng allows remote attackers to cause a denial of service

Last updated 18 August 2026

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From version 1.6.0 to before 1.6.51, an out-of-bounds read vulnerability exists in pngimagereadcomposite when processing palette images with PNGFLAGOPTIMIZEALPHA enabled. The palette compositing code in pnginitreadtransformations incorrectly applies background compositing during premultiplication, violating the invariant component ≤ alpha × 257 required by the simplified PNG API. This issue has been patched in version 1.6.51.

Libpng has been updated to version 1.6.51, which contains fixes for security vulnerabilities including CVE-2025-65018 and CVE-2025-64720.

LIBPNG has an out-of-bounds read in pngimagereadcomposite

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.6.51 to 1.6.53, there is a heap buffer over-read in the libpng simplified API function pngimagefinishread when processing interlaced 16-bit PNGs with 8-bit output format and non-minimal row stride. This is a regression introduced by the fix for CVE-2025-65018. This vulnerability is fixed in 1.6.54.

Memory leak in the pnghandletEXt 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 is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. Prior to 1.6.52, an out-of-bounds read vulnerability in libpng's simplified API allows reading up to 1012 bytes beyond the pngsRGBbase[512] array when processing valid palette PNG images with partial transparency and gamma correction. The PNG files that trigger this vulnerability are valid per the PNG specification; the bug is in libpng's internal state management. Upgrade to libpng 1.6.52 or later.

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From version 1.6.0 to before 1.6.51, there is a heap buffer overflow vulnerability in the libpng simplified API function pngimagefinishread when processing 16-bit interlaced PNGs with 8-bit output format. Attacker-crafted interlaced PNG files cause heap writes beyond allocated buffer bounds. This issue has been patched in version 1.6.51.

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From version 1.6.0 to before 1.6.51, an out-of-bounds read vulnerability exists in pngimagereadcomposite when processing palette images with PNGFLAGOPTIMIZEALPHA enabled. The palette compositing code in pnginitreadtransformations incorrectly applies background compositing during premultiplication, violating the invariant component ≤ alpha × 257 required by the simplified PNG API. This issue has been patched in version 1.6.51.

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. Prior to 1.6.55, an out-of-bounds read vulnerability exists in the pngsetquantize() API function. When the function is called with no histogram and the number of colors in the palette is more than twice the maximum supported by the user's display, certain palettes will cause the function to enter into an infinite loop that reads past the end of an internal heap-allocated buffer. The images that trigger this vulnerability are valid per the PNG specification. This vulnerability is fixed in 1.6.55.

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.

libpng 1.6.8 was released [1] and notes the following fix:

Handle zero-length PLTE chunk or NULL palette with pngerror() instead of pngchunkreport(), which by default issues a warning rather than an error, leading to later reading from a NULL pointer (pngptr->palette) in pngdoexpandpalette(). This is CVE-2013-6954 and VU#650142.

The git commit to fix is available [3].

[1] http://sourceforge.net/projects/libpng/files/libpng16/1.6.8/Gnupg/ [2] http://www.kb.cert.org/vuls/id/650142 [3] http://sourceforge.net/p/libpng/code/ci/1faa6ff32c648acfe3cf30a58d31d7aebc24968c

In libpng 1.6.34, a wrong calculation of rowfactor in the pngcheckchunklength function (pngrutil.c) may trigger an integer overflow and resultant divide-by-zero while processing a crafted PNG file, leading to a denial of service.

Multiple integer overflows in libpng before 1.5.14rc03 allow remote attackers to cause a denial of service (crash) via a crafted image to the (1) pngsetsPLT or (2) pngsettext2 function, which triggers a heap-based buffer overflow.

Integer overflow in the pngsetunknownchunks function in libpng/pngset.c in libpng before 1.5.14beta08 allows context-dependent attackers to cause a denial of service (segmentation fault and crash) via a crafted image, which triggers a heap-based buffer overflow.

An issue has been found in libpng 1.6.34. It is a SEGV in the function pngfreedata in png.c, related to the recommended error handling for pngreadimage.

DISPUTED pngcreateinfostruct in png.c in libpng 1.6.36 has a memory leak, as demonstrated by pngcp. NOTE: a third party has stated "I don't think it is libpng's job to free this buffer."

802.1X. An authentication issue was addressed with improved state management.

Buffer Overflow vulnerability in libpng 1.6.43-1.6.46 allows a local attacker to cause a denial of service via pngcreatereadstruct() function.

Buffer Overflow vulnerability in libpng 1.6.43-1.6.46 allows a local attacker to cause a denial of service via the pngimage with AddressSanitizer (ASan), the program leaks memory in various locations, eventually leading to high memory usage and causing the program to become unresponsive

A heap overflow flaw was found in libpngs' pngimage.c program. This flaw allows an attacker with local network access to pass a specially crafted PNG file to the pngimage utility, causing an application to crash, leading to a denial of service.

A use-after-free vulnerability was discovered in the pngimagefree function in the libpng library. This could lead to denial of service or a potentially exploitable crash when a malformed image is processed.

Last updated 18 August 2026

Memory leak in pngwutil.c in libpng 1.2.13beta1, and other versions before 1.2.15beta3, allows context-dependent attackers to cause a denial of service (memory leak or segmentation fault) via a JPEG image containing an iCCP chunk with a negative embedded profile length.