CVE-2018-19876

cairo 1.16.0, in cairo_ft_apply_variations() in cairo-ft-font.c, would free memory using a free function incompatible with WebKit's fastMalloc, leading to an application crash with a "free(): invalid pointer" error.

CVE-2018-18064

cairo through 1.15.14 has an out-of-bounds stack-memory write during processing of a crafted document by WebKitGTK+ because of the interaction between cairo-rectangular-scan-converter.c (the generate and render_rows functions) and cairo-image-compositor.c (the _cairo_image_spans_and_zero function).