Incus improperly handles a top-level 'templates' symlink during image unpacking and instance backup restoration. The archive unpacking code excludes device nodes but does not reject a 'templates' symlink, and the backup restore uses rsync without the '--safe-links' option. This allows a malicious image or backup to map host directories (e.g., /etc/cron.d) via the 'templates' symlink, enabling arbitrary file read and write on the host. Proof-of-concept demonstrates creating cron jobs that execute commands as root on the host.

An attacker able to import a crafted container image or instance backup can read and write arbitrary files on the host system, including sensitive configuration files. This can lead to privilege escalation and arbitrary command execution with root privileges on the host, posing a critical security risk.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid importing untrusted container images or instance backups that may contain malicious symlinks. Monitor vendor communications for updates and apply patches promptly once released.