CVE-2026-47243: Kata Containers runtime-rs virtio-fs Guest-to-Host Root Escape with PoC

Vulnerability Overview Vulnerability Name: runtime-rs: Guest-root to host-root escape via virtiofs CVE ID: CVE-2026-47243 Description: In ' , when using the standalone virtio-fs path (verified in QEMU and confirmed in Cloud Hypervisor), Kata Containers runs the host as root. If an attacker has root-equivalent execution privileges within the Kata guest VM, they can send raw FUSE requests directly to the host . Through the tested virtio-fs configuration, a raw request with an absolute path as the new symlink name will be honored outside the virtio-fs shared directory. This allows guest root to create symlinks in sensitive host paths. The PoC creates a symlink in the host's directory, causing the host to execute a guest-controlled payload as root. Impact: Guest root can execute code as host root. Affected Scope Affected Versions: <= 3.30.0 Fixed Version: 3.31.0 Affected Configuration: Remediation Use main commit . Add to the command line for standalone virtio-fs. Disable rootless mode by default for QEMU: . The QEMU configuration template generates an installation configuration using standalone virtio-fs pointing to the host binary: . The Makefile resolves these placeholders to and . selects the same standalone virtio-fs implementation whenever : . POC Code Exploitation Code Verification of Fix This proof file is created in the host's , generated by host cron. It is not created by guest processes nor by virtiofsd. Impact This PoC demonstrates guest-root to host-root command execution. Verified Host Proof This proof file is created in the host's , generated by host cron. It is not created by guest processes nor by virtiofsd. Conclusion An attacker who achieves guest root can cross the Kata isolation boundary and execute commands as host root in affected virtio-fs deployments.

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CVE-2026-47243: Kata Containers runtime-rs virtio-fs Guest-to-Host Root Escape with PoC

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