FineReport 9.0 Unauthenticated Path Traversal File Write via ReportServer

FineReport 9.0 contains a path traversal vulnerability in the /WebReport/ReportServer design_save_svg operation that allows unauthenticated attackers to write arbitrary files via the filePath parameter. Attackers can send a POST request with directory traversal sequences in filePath and a __CONTENT__ payload to write a JSP webshell and achieve remote code execution. Exploitation evidence was first observed by the Shadowserver Foundation on 2023-10-14.