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.
https://sourceware.org/bugzilla/show_bug.cgi?id=20018
https://bugzilla.redhat.com/show_bug.cgi?id=1347549
https://access.redhat.com/errata/RHSA-2019:3513
https://access.redhat.com/errata/RHSA-2019:2118
http://www.securityfocus.com/bid/106672
http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00082.html