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Incorrect AuthorizationWeakness · CWE-863

CVE-2026-6383

MEDIUM · 5.4 CVSS v3.1 Published 2026-04-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
60/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A flaw was found in KubeVirt's Role-Based Access Control (RBAC) evaluation logic. The authorization mechanism improperly truncates subresource names, leading to incorrect permission evaluations. This allows authenticated users with specific custom roles to gain unauthorized access to subresources, potentially disclosing sensitive information or performing actions they are not permitted to do. Additionally, legitimate users may be denied access to resources.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

KubeVirt's RBAC authorization logic improperly truncates subresource names during permission evaluation, causing incorrect access decisions. Authenticated users with certain custom roles can bypass restrictions to access subresources they should not have, while legitimate users may be incorrectly denied. The truncation bug affects the core authorization evaluation path.

MitigationUpgrade KubeVirt to the patched version addressing the subresource name truncation. Review and audit custom RBAC roles and bindings to identify any overly permissive configurations that could exploit this flaw, and implement least-privilege access controls.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify KubeVirt installation and version
    Run 'kubectl get kubevirts -A' to list KubeVirt installations, then check the version with 'kubectl get kubevirt -A -o jsonpath="{.items[*].status.phase}"' and compare to the known vulnerable version range
    Affected if KubeVirt is running and its version falls within the vulnerable version range where the RBAC truncation bug exists
  2. Identify custom RBAC roles with subresource permissions
    Run 'kubectl get roles -A -o json' and 'kubectl get clusterroles -o json' to list all RBAC roles, then examine the 'rules[].resources' and 'rules[].subresources' fields for custom roles that grant access to subresources
    Affected if Custom roles exist that grant broad subresource permissions that could be exploited due to the truncation bug
  3. Review role bindings for overly permissive configurations
    Run 'kubectl get rolebindings -A -o json' and 'kubectl get clusterrolebindings -o json' to examine which subjects (users, groups, service accounts) are bound to roles with subresource access
    Affected if Users or service accounts are bound to roles that could bypass restrictions due to subresource name truncation
  4. Test authorization behavior for subresource access
    Use 'kubectl auth can-i' commands to test whether users with limited roles can access subresources they should not, for example 'kubectl auth can-i get <subresource> --as=<username>' for various subresources
    Affected if Users can access subresources they should not be able to, or cannot access those they should, indicating the truncation bug is affecting authorization decisions
  5. Audit kubevirt-operator deployment
    Check the KubeVirt operator version and the kubevirt CR status with 'kubectl get kubevirt -A -o wide' to determine the exact KubeVirt version deployed in the cluster
    Affected if The deployed KubeVirt version matches the vulnerable version range for this CVE

A user is affected if KubeVirt is installed with a version impacted by the RBAC subresource name truncation bug and the environment contains custom RBAC roles or bindings that could trigger the flawed authorization path.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade KubeVirt to the patched version addressing the subresource name truncation. Review and audit custom RBAC roles and bindings to identify any overly permissive configurations that could exploit this flaw, and implement least-privilege access controls.

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA6.0 h
42.0 hours of engineering $7,360
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-6383 in production — separate from our analysis above.

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