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 Core before 2026.6.0 contains a path traversal vulnerability that allows unauthenticated attackers to write arbitrary files to any directory on the host filesystem by uploading a crafted backup archive during the initial onboarding window. Attackers can manipulate the 'name' field inside the uploaded archive's backup.json to supply an absolute path, causing pathlib.Path.truediv to discard the configured backup directory prefix and write attacker-controlled content to arbitrary locations, with full filesystem access when the process runs as root.

Home Assistant Core before 2026.5.4 contains a cross-site scripting vulnerability in the Shelly integration's asyncgetmediaimage() method that allows attackers controlling a Shelly device's thumb field to serve arbitrary HTML content by supplying a data URI with a text/html content type without validation against an image-only allowlist. Attackers can cause the media player proxy endpoint to serve attacker-controlled bytes with Content-Type text/html in the Home Assistant web origin, enabling theft of session tokens from local storage and authenticated calls to sensitive service endpoints including lock, alarm, and cover controls.