GraphicsMagick is a collection of tools to read, write and manipulate images in many formats.
The SetImageInfo function was found vulnerable to a format string mishandling. Daniel Kobras discovered that the handling of "%"-escaped sequences in filenames passed to the function is inadequate in ImageMagick GLSA 200602-06 and the same vulnerability exists in GraphicsMagick.
By feeding specially crafted file names to GraphicsMagick an attacker can crash the program and possibly execute arbitrary code with the privileges of the user running GraphicsMagick.
There is no known workaround at this time.
All GraphicsMagick users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=media-gfx/graphicsmagick-1.1.7"