Wekan: Arbitrary file read and server DoS via attachment versions.original.path

Wekan is open source kanban built with Meteor. Prior to 9.31, Wekan allows a logged-in board member to insert an attachment document through the /attachments/insert DDP method with attacker-controlled versions.original.path and versions.original.storage fields. The server/permissions/attachments.js insert rule checks only board write access, and FileStoreStrategyFilesystem.getReadStream() in models/lib/fileStoreStrategy.js streams the stored path without a storage-root containment check, allowing arbitrary file reads and denial of service through special files such as /dev/zero. This issue is fixed in version 9.31.