{"id":"CVE-2026-64676","aliases":["AZL-94685","EUVD-2026-54711","GHSA-h8jv-63p2-496x"],"status":"published","title":"Kata Containers: Unauthorized mem-agent ttRPC methods let an untrusted host tamper with confidential-guest memory","description":"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.","severity":{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00175,"percentile":0.07093,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-862"],"published":"2026-08-07T21:47:20Z","modified":"2026-11-05T05:36:30Z","affected":[{"source":"osv","ecosystem":"Azure Linux:3","package":"kata-containers-preview","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"3.27.0~preview2-2"}]}]}],"products":[{"vendor":"kata-containers","product":"kata-containers"}],"references":[{"url":"https://github.com/kata-containers/kata-containers/security/advisories/GHSA-h8jv-63p2-496x","tags":["x_refsource_CONFIRM","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64676","tags":["web","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64676.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-64676","title":"Kata Containers: Unauthorized mem-agent ttRPC methods let an untrusted host tamper with confidential-guest memory","description":"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.","status":"published","published":"2026-08-07T21:47:20.584Z","modified":"2026-08-13T18:08:55.815Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:19:57.818032Z"}],"euvd":[{"id":"EUVD-2026-54711","description":"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.","status":"published","published":"2026-08-07T21:47:20Z","modified":"2026-08-13T18:08:55Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L","level":"medium"}],"updated_at":"2026-11-02T18:01:55.61982Z"}],"nvd":[{"id":"CVE-2026-64676","description":"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.","status":"published","published":"2026-08-07T22:16:59.48Z","modified":"2026-09-09T21:02:22.66Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:12:35.743275Z"}],"osv":[{"id":"CVE-2026-64676","title":"Kata Containers: Unauthorized mem-agent ttRPC methods let an untrusted host tamper with confidential-guest memory","description":"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.","status":"published","published":"2026-08-07T21:47:20.584Z","modified":"2026-10-28T02:31:02.622916561Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T15:45:14.096824Z"},{"id":"AZL-94685","title":"CVE-2026-64676 affecting package kata-containers-preview 3.27.0~preview2-2","description":"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.","status":"published","published":"2026-08-07T22:16:59Z","modified":"2026-11-05T05:36:30Z","updated_at":"2026-11-05T16:41:26.077208Z"}]}}