YiShaAdmin 3.1 Unauthenticated Path Traversal via DownloadFile endpoint

YiShaAdmin 2.2 through 3.1, fixed in commit 025b062, contains an unauthenticated path traversal vulnerability in the /admin/File/DownloadFile endpoint that allows attackers to read and delete arbitrary files via the filePath parameter. Attackers can send crafted GET requests with directory traversal sequences in filePath and set the delete parameter to read or remove system files like etc/passwd. Exploitation evidence was first observed by the Shadowserver Foundation on 2023-10-20.