Out-of-directory file writes via unsanitized tag paths

Path traversal in Fluent Bit before 4.0.12 allows remote attackers to write files outside the configured directory via crafted tags. When the out_file plugin's File option is omitted, its flush path uses the untrusted record tag as a filename without sanitizing traversal segments. Exposure requires a network-reachable input that lets an attacker control tags and an out_file output lacking File; successful exploitation alters files writable by the Fluent Bit process.