ApostropheCMS: Arbitrary file read via import-export attachment-name path traversal

ApostropheCMS is an open-source Node.js content management system. Prior to 3.6.2, the import-export module in packages/import-export/lib/formats/gzip.js constructs an attachment source path from the attacker-controlled _id, name, and extension fields in aposAttachments.json without ensuring that the resolved path remains under the extracted attachments directory, allowing an authenticated contributor to import a crafted archive, read a host file with an allowed extension, and publish the copied file at an unauthenticated uploads URL. This issue is fixed in version 3.6.2.