Dozzle: SSRF guard bypass via IPv6 transition addresses (6to4/NAT64/Teredo) in webhook notification dispatcher

Summary The isBlockedIP SSRF guard in Dozzle's webhook notification dispatcher blocks loopback, link-local, multicast, and unspecified addresses but does not recognize IPv6 transition mechanism addresses RFC 3056 6to4, RFC 6052 NAT64, RFC 4380 Teredo that embed arbitrary IPv4 addresses. An...