CVE-2026-50540

Kata Containers prior to version 3.31.0 is vulnerable to a guest-root to host-root escape in the standalone virtio-fs path. In this configuration, the host virtiofsd runs as root with --sandbox none --seccomp none, allowing an attacker with root access in the guest to bypass the guest virtio-fs client and submit raw FUSE requests to the host virtiofsd, creating symlinks in sensitive host locations such as /etc/cron.d, leading to host code execution as root.

In Kata Containers prior to version 3.31.0, the default configuration allows pod creators to inject arbitrary command-line arguments into the virtiofsd process through the `io.katacontainers.config.hypervisor.virtio_fs_extra_args` pod annotation. By injecting `-o source=/` along with `--no-announce-submounts` and `--sandbox=none`, an attacker can override the virtiofsd shared directory to serve the entire host root filesystem into the guest VM. Combined with the `kernel_params` annotation (also enabled by default) to activate the agent debug console, the attacker can mount the host filesystem from inside the VM and read or write any file on the host, including /etc/shadow.

A vulnerability in Kata Containers prior to version 3.27.0 with Cloud Hypervisor allows a container user to modify the guest VM filesystem, leading to arbitrary code execution as root in that VM. The issue does not affect the host or other containers/VMs on the same host, but on arm64 with QEMU lacking NVDIMM read-only support, a guest write could reach the image file.

In Kata Containers, configurations using genpolicy for Confidential Containers guest protection, a malicious host operator can exploit insufficient validation of CreateContainer mount and storage rules, allowing mounting arbitrary container-rootfs paths over sensitive host locations or provisioning arbitrary content.

Kata Containers before version 4.0.0 has an authorization bypass vulnerability in confidential-guest memory management. Two ttRPC methods introduced with the mem-agent feature lack the AgentPolicy authorization check, allowing an untrusted host to manipulate guest memory when mem-agent is enabled (off by default). The impact is limited to availability and performance degradation, not memory disclosure or code execution.

A vulnerability in Kata Containers from version 3.4.0 to 3.28.0 allows an untrusted host to write to arbitrary locations inside the guest workload image. This can lead to overwriting binaries in the guest and exfiltrating data from containers, including those running in Confidential VMs (CVMs).