dbcve.org
KyvernoApplication · Nirmata

CVE-2023-34091

MEDIUM · 6.5 CVSS v3.1 Published 2023-06-01
Fix available
A fix is available. Upgrade to 1.10.0 or later.
See remediation →
71/100
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
Kyverno is a policy engine designed for Kubernetes. In versions of Kyverno prior to 1.10.0, resources which have the `deletionTimestamp` field defined can bypass validate, generate, or mutate-existing policies, even in cases where the `validationFailureAction` field is set to `Enforce`. This situation occurs as resources pending deletion were being consciously exempted by Kyverno, as a way to reduce processing load as policies are typically not applied to objects which are being deleted. However, this could potentially result in allowing a malicious user to leverage the Kubernetes finalizers feature by setting a finalizer which causes the Kubernetes API server to set the `deletionTimestamp` and then not completing the delete operation as a way to explicitly to bypass a Kyverno policy. Note that this is not applicable to Kubernetes Pods but, as an example, a Kubernetes Service resource can be manipulated using an indefinite finalizer to bypass policies. This is resolved in Kyverno 1.10.0. There is no known workaround.

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 · high confidence

Kyverno versions prior to 1.10.0 incorrectly exempt resources with a `deletionTimestamp` from all policy enforcement (validate, generate, mutate-existing), even when `validationFailureAction` is set to `Enforce`. Attackers can exploit this by adding a finalizer that triggers `deletionTimestamp` without completing deletion, allowing them to bypass policy controls on resources like Services.

MitigationUpgrade Kyverno to version 1.10.0 or later. No workaround exists; this is a mandatory upgrade to remediate the vulnerability.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
KyvernoApplication
Affected:< 1.10.0

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
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/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. Identify installed Kyverno version
    Run `kubectl get deployment -n kyverno kyverno -o jsonpath='{.spec.template.spec.containers[*].image}'` or check your Helm release version
    Affected if The returned version is earlier than 1.10.0
  2. Verify Kyverno policies with Enforce mode exist
    Run `kubectl get cpol,clusterpolicy -o jsonpath='{range .items[*]}{.metadata.name}{"\n"}{.spec.validationFailureAction}{"\n"}{end}'`
    Affected if Any policy shows `validationFailureAction: Enforce` and Kyverno version is below 1.10.0
  3. Check for resources with deletionTimestamp
    Run `kubectl get all --all-namespaces -o jsonpath='{range .items[?(@.metadata.deletionTimestamp)]}{.kind}{"/"}{.metadata.namespace}{"/"}{.metadata.name}{"\t"}{.metadata.deletionTimestamp}{"\n"}{end}'`
    Affected if Resources exist with deletionTimestamp set while Kyverno is below 1.10.0 and Enforce policies are present
  4. Review resources with finalizers that could set deletionTimestamp
    Run `kubectl get all --all-namespaces -o jsonpath='{range .items[?(@.metadata.finalizers)]}{.kind}{"/"}{.metadata.namespace}{"/"}{.metadata.name}{"\n"}{end}'`
    Affected if Finalizers are present on resources and Kyverno version is below 1.10.0 with Enforce policies configured

You are affected if running any Kyverno version prior to 1.10.0 AND you have policies set to validationFailureAction: Enforce, combined with resources that have deletionTimestamp set (or finalizers that could trigger it) in your cluster.

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.

dbcve · scoped
Upgrade available Upgrade to 1.10.0 or later
Fixed in 1.10.0
Interim mitigation

Upgrade Kyverno to version 1.10.0 or later. No workaround exists; this is a mandatory upgrade to remediate the vulnerability.

Recommended fix High confidence

Kyverno 1.10.0

  1. Upgrade Kyverno to version 1.10.0 or later to resolve the policy bypass vulnerability.
  2. Verify the upgrade by checking that Kyverno is enforcing policies on resources with deletionTimestamp set (e.g., resources with finalizers that keep them in a deleting state).
  3. Test your existing policies to ensure they work correctly after the upgrade, particularly any policies that should apply to resources being deleted.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Kyverno Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
Get the upgrade done

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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-2023-34091 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data