c-ares is an asynchronous resolver library. ares_inet_net_pton() is vulnerable to a buffer underflow for certain ipv6 addresses, in particular "0::00:00:00/2" was found to cause an issue. C-ares only uses this function internally for configuration purposes which would require an administrator to configure such an address via ares_set_sortlist(). However, users may externally use ares_inet_net_pton() for other purposes and thus be vulnerable to more severe issues. This issue has been fixed in 1.19.1.
Exploitability
AV:LAC:HPR:HUI:NScope
S:UImpact
C:NI:NA:H4.1/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:HOther