Quantum Secular Labs / Blog / Advisories
CVE-2026-122311: Tenants who can create a NamespacedValidatingPolicy can insert .. segments to read and write arbitrary…
CVE-2026-122311 is rated critical with a CVSS v3.1 base score of 9.9. Per its scoring, it can be exploited over the network, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.
Vulnerability description
Kyverno from 1.16.0 before 1.19.2 fails to validate path segments in the resource argument of resource.get() and resource.post(), allowing namespaced CEL policies to escape their namespace. Tenants who can create a NamespacedValidatingPolicy can insert .. segments to read and write arbitrary cluster objects using the admission controller's ServiceAccount, leading to cluster takeover.
Severity breakdown
CVSS v3.1 9.9: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
- Attack complexity: Low. No special conditions; the attack can be repeated reliably.
- Privileges required: Low. A basic user account is enough.
- User interaction: None. No action from any user is needed.
- Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
- Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
- Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
- Availability impact: High. Total loss of availability; the component can be shut down.
Underlying weakness
CWE-22: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.