CVE-2026-44210 in Kata Containers
Summary
by MITRE • 07/23/2026
Kata Containers is an open source project focusing on a standard implementation of lightweight Virtual Machines (VMs) that perform like containers. Versions prior to 3.31.0 ship with a default configuration that 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. Version 3.31.0 patches the issue.
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Analysis
by VulDB Data Team • 07/23/2026
This vulnerability exists within Kata Containers, an open source project designed to provide lightweight virtual machines that operate with container-like performance characteristics. The flaw manifests in default configurations prior to version 3.31.0 where pod creators can inject arbitrary command-line arguments into the virtiofsd process through specific pod annotations. This represents a critical privilege escalation vulnerability that directly violates the fundamental security principles of container isolation and virtual machine separation.
The technical implementation of this vulnerability leverages the `io.katacontainers.config.hypervisor.virtio_fs_extra_args` pod annotation to inject malicious arguments into the virtiofsd process, which serves as the filesystem backend for Kata Containers. When attackers combine `-o source=/` with `--no-announce-submounts` and `--sandbox=none` flags, they can override the intended virtiofsd shared directory to expose the entire host root filesystem within the guest VM. This configuration bypasses normal filesystem access controls and allows complete traversal of the host operating system's file hierarchy from within the isolated container environment.
The operational impact of this vulnerability extends beyond simple privilege escalation to enable full host compromise when combined with additional default configurations. The `kernel_params` annotation, also enabled by default, activates the agent debug console which provides attackers with additional attack surface for exploitation. Once inside the VM, adversaries can mount the host filesystem and gain read-write access to any file on the host system including critical security files like /etc/shadow that contain password hashes and authentication data.
This vulnerability aligns with CWE-276 (Improper Default Permissions) and CWE-434 (Unrestricted Upload of File with Dangerous Type) while mapping to ATT&CK techniques including T1059 (Command and Scripting Interpreter), T1078 (Valid Accounts), and T1565 (Data Manipulation). The attack vector demonstrates a classic privilege escalation pattern where an unprivileged user gains administrative access through improper configuration defaults. Organizations using Kata Containers should immediately upgrade to version 3.31.0 or later, disable unnecessary pod annotations, implement strict pod security policies, and conduct comprehensive security audits of their container orchestration environments to prevent exploitation of this critical vulnerability that fundamentally undermines the security model of containerized applications.
The patch implemented in version 3.31.0 addresses this specific issue by removing the default configuration that allows arbitrary command-line arguments to be injected into virtiofsd processes, thereby restoring proper isolation between host and guest environments while maintaining necessary functionality for legitimate use cases.