CVE-2026-64676
MediumCVSS 5.7Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
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.
Risk Assessment
The risk involves potential degradation of performance and availability of confidential workloads in Confidential Containers deployments if mem-agent is enabled. An attacker host can force swap, aggressive eviction, or compaction, affecting service stability.
Recommendation
Upgrade to version 4.0.0 or later. If mem-agent is not required, keep it disabled to avoid exposure to this vulnerability.
Original NVD description (English source)
Kata Containers is an open source implementation of lightweight Virtual Machines (VMs) that perform like containers. In versions prior to 4.0.0, the kata-agent is vulnerable to an authorization bypass in confidential-guest memory management. In Confidential Containers (CoCo) deployments, the kata-agent enforces an OPA/Rego-based AgentPolicy that must authorize every ttRPC API call, forming the security boundary that prevents an untrusted host from directing the confidential guest. Two ttRPC methods introduced with the mem-agent feature are missing this authorization check, so an untrusted host can invoke them unconditionally regardless of the guest's policy configuration. When mem-agent is enabled (off by default), this lets the host tamper with in-guest memory management by forcing swap, aggressive eviction, or compaction, resulting in attacker-controlled availability and performance degradation of the confidential workload entirely outside the agent-policy boundary. The impact does not include memory disclosure or code execution, and severity is bounded by the precondition that mem-agent must be explicitly enabled. This issue is fixed in version 4.0.0.