Strix
26.1K

CVE-2023-34091

MEDIUMCVSS 6.5/10EPSS 0.50%

Last modified

CVE-2023-34091 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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`. EPSS estimates a 0.50% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
6.5/10

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

EPSS Probability
0.50%

38.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
NirmataKyverno< 1.10.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2023-34091?
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.
How severe is CVE-2023-34091?
CVE-2023-34091 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.50% probability of exploitation in the next 30 days.
How do I fix CVE-2023-34091?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2023

View all 2023CVEs →

Are you affected by CVE-2023-34091?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST