telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root" value for the USER environment variable.

{
                    "defaultStatus": "unknown",
                    "product": "Inetutils",
                    "vendor": "GNU",
                    "versions": [
                        {
                            "lessThanOrEqual": "2.7",
                            "status": "affected",
                            "version": "1.9.3",
                            "versionType": "custom"
                        }
                    ]
                }