Weaver (Fanwei) E-office versions prior to 10.0_20221201 contain an unauthenticated arbitrary file upload vulnerability in the OfficeServer.php endpoint that allows remote attackers to upload malicious files by sending multipart POST requests with arbitrary filenames and disguised content types. Attackers can upload PHP webshells to the Document directory and execute them via HTTP GET requests to achieve remote code execution as the web server user. Exploitation evidence was first observed by the Shadowserver Foundation on 2022-10-10 (UTC).