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.