Cairo is a 2D vector graphics library with cross-device output support.
Multiple integer overflows were reported, one of which Peter Valchev (Google Security) found to be leading to a heap-based buffer overflow in the cairo_image_surface_create_from_png() function that processes PNG images.
A remote attacker could entice a user to view or process a specially crafted PNG image file in an application linked against Cairo, possibly leading to the execution of arbitrary code with the privileges of the user running the application.
There is no known workaround at this time.
All Cairo users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=x11-libs/cairo-1.4.12"