There is a heap based buffer over-read in lexer.hpp of LibSass 3.4.5, and 3.5.0.beta.1 through 3.5.0.beta.3. A crafted input will lead to a remote denial of service attack.
CWE-125 - Out-of-Bounds Read
Out-of-bounds read is a vulnerability that allows access to memory beyond the authorized accessible location. Such a vulnerability compromises the confidentiality of the trusted environment in the application and enables an attacker to launch further attacks by leveraging the exposed information.