The cr_tknzr_parse_rgb function in cr-tknzr.c in libcroco 0.6.11 and 0.6.12 has an "outside the range of representable values of type long" undefined behavior issue, which might allow remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted CSS file. NOTE: third-party analysis reports "This is not a security issue in my view. The conversion surely is truncating the double into a long value, but there is no impact as the value is one of the RGB components.
https://security.gentoo.org/glsa/201707-13
https://git.gnome.org/browse/libcroco/commit/?id=9ad72875e9f08e4c519ef63d44cdbd94aa9504f7
https://bugzilla.suse.com/show_bug.cgi?id=1034482
https://blogs.gentoo.org/ago/2017/04/17/libcroco-heap-overflow-and-undefined-behavior/
http://openwall.com/lists/oss-security/2017/04/24/2
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00043.html