CVE-2026-122303

Critical CVSS 9.9

Published 2026-11-05 · last changed 2026-11-05

The fix

We hold no Microsoft remediation data for CVE-2026-122303, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

Kyverno from 1.17.0 before 1.19.2 contains an authorization bypass vulnerability that allows namespace tenants to overwrite resources in other namespaces via NamespacedMutatingPolicy mutate-existing targetMatchConstraints.expression. Attackers can return a CEL map literal fabricating a target with an attacker-chosen metadata.namespace, causing the privileged background controller to overwrite Secrets, Deployments, or policies cluster-wide.

Sources

NVD record for CVE-2026-122303

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