c-ares is a C library for asynchronous DNS requests. 'ares__read_line' is used to parse local configuration files such as '/etc/resolv.conf', '/etc/nsswitch.conf', the 'HOSTALIASES' file, and if using a c-ares version prior to 1.27.0, the '/etc/hosts' file. If any of these configuration files has an embedded 'NULL' character as the first character in a new line, it can lead to attempting to read memory prior to the start of the given buffer which may result in a crash. This issue is fixed in c-ares 1.27.0. No known workarounds exist