CVE-2026-41230: Froxlor has a BIND Zone File Injection via Unsanitized DNS Record Content in DomainZones::add()

Froxlor is open source server administration software. Prior to version 2.3.6, `DomainZones::add()` accepts arbitrary DNS record types without a whitelist and does not sanitize newline characters in the `content` field. When a DNS type not covered by the if/elseif validation chain is submitted (e.g., `NAPTR`, `PTR`, `HINFO`), content validation is entirely bypassed. Embedded newline characters in the content survive `trim()` processing, are stored in the database, and are written directly into BIND zone files via `DnsEntry::__toString()`. An authenticated customer can inject arbitrary DNS records and BIND directives (`$INCLUDE`, `$ORIGIN`, `$GENERATE`) into their domain's zone file. Version 2.3.6 fixes the issue.