OptiPNG is a PNG optimizer that recompresses image files to a smaller size, without losing any information.
A use-after-free vulnerability exists in the palette reduction functionality of OptiPNG.
A remote attacker could entice a user to open a specially crafted image file, possibly resulting in execution of arbitrary code with the privileges of the process or a Denial of Service condition.
There is no known workaround at this time.
All OptiPNG users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=media-gfx/optipng-0.7.3"