CVE-2026-47243

Name of the Vulnerable Software and Affected Versions Kata Containers versions prior to 3.31.0

Description In the runtime-rs standalone virtio-fs path, the host virtiofsd is run as root with --sandbox none and --seccomp none. An attacker with root-equivalent access inside the guest VM can bypass the guest virtio-fs client by taking over the virtio-fs PCI device and building a virtqueue in userspace to submit raw FUSE (Filesystem in Userspace) requests directly to the host virtiofsd. By sending a crafted FUSE SYMLINK request with an absolute host path as the new symlink name, the attacker can create root-owned symlinks in sensitive host locations, such as /etc/cron.d, outside the configured shared directory. This allows the attacker to point a symlink to a guest-controlled crontab payload, which the host cron daemon then executes as host root, resulting in a guest-to-host escape.

Recommendations Update Kata Containers to version 3.31.0. As a temporary mitigation, restrict the use of the standalone virtio-fs path in runtime-rs or ensure virtiofsd is not run with --sandbox none and --seccomp none.