library/std/src/net/parser.rs in Rust before 1.53.0 does not properly consider extraneous zero characters at the beginning of an IP address string, which (in some situations) allows attackers to bypass access control that is based on IP addresses, because of unexpected octal interpretation.
https://security.gentoo.org/glsa/202210-09
https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-015.md
https://github.com/rust-lang/rust/pull/83652
https://github.com/rust-lang/rust/issues/83648
https://doc.rust-lang.org/beta/std/net/struct.Ipv4Addr.html
https://defcon.org/html/defcon-29/dc-29-speakers.html#kaoudis