CVE-2026-63502: Yeti: Path traversal in ExportTask name allows authenticated arbitrary file read and write

Yeti bridges the gap between CTI and DFIR practitioners by providing a Forensics Intelligence platform and pipeline. Prior to 2.5.1, YETI derives ExportTask.filename from the user-controlled task name and passes it to core/clients/filestorage/classes/localstorage.py without sanitizing traversal sequences or enforcing path confinement. A low-privileged authenticated user using the default local storage backend can call POST /api/v2/tasks/export/new with a traversal name and use ExportTask.filecontents through GET /api/v2/tasks/export/{exportid}/content to read files accessible to the YETI service account. Running ExportTask.run() can also write attacker-controlled export output to an attacker-selected writable path. The impact depends on the service account's filesystem permissions, and universal code execution is not established. This issue is fixed in version 2.5.1.