(RHSA-2005:793) netpbm security update

The netpbm package contains a library of functions that support
programs for handling various graphics file formats, including .pbm
(portable bitmaps), .pgm (portable graymaps), .pnm (portable anymaps),
.ppm (portable pixmaps) and others.

A bug was found in the way netpbm converts Portable Anymap (PNM) files into
Portable Network Graphics (PNG). The usage of uninitialised variables in
the pnmtopng code allows an attacker to change stack contents when
converting to PNG files with pnmtopng using the ‘-trans’ option. This may
allow an attacker to execute arbitrary code. The Common Vulnerabilities
and Exposures project assigned the name CAN-2005-2978 to this issue.

All users of netpbm should upgrade to the updated packages, which
contain a backported patch to resolve this issue.