CVE-2026-64676 — Kata Containers: Unauthorized mem-agent ttRPC methods let an untrusted host tamper with confidential-guest memory
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Katacontainers Kata Containers).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Katacontainers | Kata Containers | version < 4.0.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.7 | CVSS 3.1 | Medium | 2.5 | 2.7 | security-advisories@github.com via NIST National Vulnerability Database |
| 5.7 | CVSS 3.1 | Medium | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L (score shown at the top: security-advisories@github.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Audit administrative actions and access to resources outside each user’s normal pattern.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · kata-containers/kata-containers
- SSVC assessment updated
- Record published
- CVSS changed · 5.7
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-47243 Kata guest escape: runtime-rs guest-root to host-root escape via virtiofs Aug 7, 2026
- Critical CVE-2026-50540 Kata Containers: Config Path Annotation Arbitrary File Loading Aug 7, 2026
- Critical CVE-2026-44210 Kata Containers have VM Escape via virtiofsd Argument Injection through Default-Enabled Pod Annotations Jul 23, 2026
- High CVE-2026-41326 Kata Containers: CopyFile Policy Subversion via Symlinks Apr 24, 2026
- High CVE-2026-24834 Kata Container to Guest micro VM privilege escalation Feb 19, 2026
- Critical CVE-2026-24054 Kata Containers: improper handling of empty rootfs triggers host block device hotplug Jan 29, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-64676 is "Kata Containers: Unauthorized mem-agent ttRPC methods let an untrusted host tamper with confidential-guest memory", rated Medium. It affects Kata Containers (Katacontainers); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.7 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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