CVE-2023-34091 Kyverno resource with a deletionTimestamp may allow policy circumvention

What is CVE-2023-34091?

CVE-2023-34091 is a medium-severity missing authorization vulnerability in kyverno, published on 1 Jun 2023. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

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.

Weakness: CWE-285

Which versions are affected by CVE-2023-34091?

3 open source packages ship an affected version, including github.com/kyverno/kyverno. It affects 1 product.

Products include Nirmata Kyverno.

How do I fix CVE-2023-34091?

Upgrade github.com/kyverno/kyverno to 1.10.0 or later.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2023-34091 being exploited?

There is no known exploitation of CVE-2023-34091 in the wild and no public exploit code.

Other vulnerabilities in kyverno

• CVE-2024-48921 Kyverno's PolicyException objects can be created in any namespace by default High 8.7
• CVE-2023-42813 Denial of service from malicious manifest in kyverno Medium 6.1
• CVE-2023-42816 Denial of service from malicious signature in kyverno Medium 6.1
• CVE-2023-33191 kyverno seccomp control can be circumvented Medium 4.6
• CVE-2023-42814 Denial of service from malicious image manifest in kyverno Low 3.1

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CLEANSTART-2025-XQ01253, CLEANSTART-2026-FU09912, GHSA-hq4m-4948-64cc, GO-2023-1819.