Dolibarr 9.0.0 through 23.0.4 saves inbound email attachments under the name supplied in the message's MIME headers without reducing it to a safe basename. The global saveAttachment() in htdocs/emailcollector/lib/emailcollector.lib.php builds $filepath = $path . $filename . '.' . $ext and hands it to file_put_contents(), and the private saveAttachment() in htdocs/emailcollector/class/emailcollector.class.php writes to $destdir.'/'.$filename; the name reaches both from the attachment's own getName() or getFilename() value by way of the record-join, create-ticket and create-project operations. A traversal sequence in the filename therefore survives intact, so any sender who can email a mailbox that an EmailCollector monitors, which is the module's ordinary use for a support or ticket inbox, can place attacker-controlled content outside the per-object attachment directory without holding a Dolibarr account. Under the hardened layout Dolibarr's SECURITY.md requires, with htdocs read-only,

Dolibarr 9.0.0 through 23.0.4 saves inbound email attachments under the name supplied in the message's MIME headers without reducing it to a safe basename. The global saveAttachment() in htdocs/emailcollector/lib/emailcollector.lib.php builds $filepath = $path . $filename . '.' . $ext and hands it to file_put_contents(), and the private saveAttachment() in htdocs/emailcollector/class/emailcollector.class.php writes to $destdir.'/'.$filename; the name reaches both from the attachment's own getName() or getFilename() value by way of the record-join, create-ticket and create-project operations. A traversal sequence in the filename therefore survives intact, so any sender who can email a mailbox that an EmailCollector monitors, which is the module's ordinary use for a support or ticket inbox, can place attacker-controlled content outside the per-object attachment directory without holding a Dolibarr account. Under the hardened layout Dolibarr's SECURITY.md requires, with htdocs read-onl...