Is CVE-2026-122303 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-122303 being exploited in the wild.

How severe is CVE-2026-122303?

Critical severity, with a CVSS score of 9.9, published 5 November 2026.

Is there a fix for CVE-2026-122303?

Yes: fixed in 1.19.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-122303 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-122303?

Check whether you run Kyverno at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-122303: Kyverno NamespacedMutatingPolicy authorization bypass in mutate-existing

CVE-2026-122303 · Severity: critical · CVSS 9.9 · Published 2026-11-05

Kyverno is a policy engine for Kubernetes that enforces security and compliance rules. A namespace tenant with permission to create policies in their own namespace can bypass authorization controls and overwrite critical resources in other namespaces or cluster-wide—including Secrets, Deployments, and security policies themselves—using Kyverno's privileged background controller. This allows an attacker with limited permissions to gain complete control over cluster resources.

Technologies: Kyverno. Vendors: Kyverno.

Quick answers

Is CVE-2026-122303 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-122303 being exploited in the wild.
How severe is CVE-2026-122303?: Critical severity, with a CVSS score of 9.9, published 5 November 2026.
Which products and versions are affected?: Kyverno 1.17.0 before 1.19.2.
Is there a fix for CVE-2026-122303?: Yes: fixed in 1.19.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-122303 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-122303?: Check whether you run Kyverno at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: 1.19.2

Technical details

The vulnerability exists in NamespacedMutatingPolicy with mutate-existing evaluation enabled, where a raw CEL expression in targetMatchConstraints.expression can fabricate a target object with an arbitrary metadata.namespace field. The background processor resolves these targets without namespace confinement checks and applies mutations via the privileged background ServiceAccount with no per-target authorization validation. Additionally, a secondary escape permits cluster-wide mutation of Namespace objects when the target kind is Namespace.

Affected products

Kyverno Kyverno 1.17.0 before 1.19.2

Timeline

2026-10-21: disclosed
2026-11-05: advisory

References

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