Home Assistant Core before v2025.8.0 is vulnerable to Directory Traversal. The Downloader integration does not fully validate file paths during concatenation, leaving a path traversal vulnerability.

Home Assistant Core before 2026.7.0 contains a path traversal vulnerability in the backup-restore function that allows attackers to write files to arbitrary absolute filesystem paths by supplying a crafted tar archive with a SYMTYPE entry containing a benign member name paired with an absolute linkname pointing outside the extraction directory. Because the official Docker image runs the Home Assistant process as root and the subsequent regular-file entry is written through the unvalidated symlink, attackers can achieve remote code execution by overwriting auto-imported Python paths such as site-packages/sitecustomize.py or custom component directories.

Home Assistant before 2021.1.3 does not have a protection layer that can help to prevent directory-traversal attacks against custom integrations. NOTE: the vendor's perspective is that the vulnerability itself is in custom integrations written by third parties, not in Home Assistant; however, Home Assistant does have a security update that is worthwhile in addressing this situation