There is a heap-based buffer over-read in the Sass::Prelexer::re_linebreak function in lexer.cpp in LibSass 3.4.5. A crafted input will lead to a remote denial of service attack.
{ "urgency": "not yet assigned" }
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2017-11608.json"