In LibSass 3.5.5, a heap-based buffer over-read exists in Sass::Prelexer::alternatives in prelexer.hpp.
https://github.com/sass/libsass/issues/2816
http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00027.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00051.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00047.html