In the GNU C Library (aka glibc or libc6) through 2.28, the getaddrinfo function would successfully parse a string that contained an IPv4 address followed by whitespace and arbitrary characters, which could lead applications to incorrectly assume that it had parsed a valid string, without the possibility of embedded HTTP headers or other potentially dangerous substrings.
http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00082.html
https://access.redhat.com/errata/RHSA-2019:2118
https://access.redhat.com/errata/RHSA-2019:3513