Vulnerability Note VU#817368

libpng png_handle_sBIT() performs insufficient bounds checking

Original Release date: 04 Aug 2004 | Last revised: 14 Jun 2005


The Portable Network Graphics library (libpng) contains a flaw that could introduce a remotely exploitable vulnerability.


The Portable Network Graphics (PNG) image format is used as an alternative to other image formats such as the Graphics Interchange Format (GIF). The libpng reference library is available for application developers to support the PNG image format.

A potentially insufficient bounds check error exists within the png_handle_sBIT() function. A similar error exists in the png_handle_hIST() function. While the code that contains these errors could potentially permit a buffer overflow to occur during a subsequent png_crc_read() operation, it is unclear what practical vulnerabilities they might present in applications using libpng.

Multiple applications support the PNG image format, including web browsers, email clients, and various graphic utilities. Because multiple products have used the libpng reference library to implement native PNG image processing, multiple applications will be affected by this issue in different ways.

Please note that this vulnerability is known to exist in Microsoft Windows Messenger and MSN Messenger. Please see MS05-009 for more details. For information regarding how this vulnerability affects Microsoft Internet Explorer, refer to MS05-025.


The complete impact of this vulnerability is not yet known.


Apply a patch from the vendor

Patches have been released to address this vulnerability. Please see the Systems Affected section of this document for more details.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
GentooAffected-20 Aug 2004
libpng.orgAffected16 Jul 200404 Aug 2004
Microsoft CorporationAffected16 Jul 200414 Jun 2005
OpenPKGAffected-20 Aug 2004
SlackwareAffected-20 Aug 2004
Trustix Secure LinuxAffected-20 Aug 2004
Juniper NetworksNot Affected16 Jul 200423 Jul 2004
NEC CorporationNot Affected16 Jul 200403 Aug 2004
Apple Computer Inc.Unknown16 Jul 200417 May 2005
BSDIUnknown-23 Jul 2004
ConectivaUnknown-23 Jul 2004
Cray Inc.Unknown-23 Jul 2004
DebianUnknown-23 Jul 2004
eMC CorporationUnknown-23 Jul 2004
EngardeUnknown-23 Jul 2004
If you are a vendor and your product is affected, let us know.View More »

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A



Thanks to Chris Evans for reporting this vulnerability.

This document was written by Chad Dougherty and Damon Morda.

Other Information

  • CVE IDs: CAN-2004-0597
  • Date Public: 04 Aug 2004
  • Date First Published: 04 Aug 2004
  • Date Last Updated: 14 Jun 2005
  • Severity Metric: 0.76
  • Document Revision: 18


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