CVE-2026-22872

Severity CVSS v4.0:

MEDIUM

Type:

CWE-20 Input Validation

Publication date:

01/06/2026

Last modified:

03/06/2026

Description

Capsule is a multi-tenancy and policy-based framework for Kubernetes. The Capsule Controller runs with cluster-admin privileges. Although the TenantResource RawItems processing logic forcibly sets the namespace, this is ineffective for cluster-scoped resources. Prior to version 0.13.0, tenant administrators can leverage the Controller&#39;s elevated privileges to create cluster-scoped resources (such as ClusterRole and ValidatingWebhookConfiguration) that they cannot create directly, achieving cross-tenant privilege escalation and cluster-level attacks. The attack vector has a few limiting factors. This attack requires Tenant Owner privileges and requires Capsule Controller running with cluster-admin privileges (default configuration). Additionally, some clusters may have additional admission controllers blocking malicious resources. Version 0.13.0 patches this issue.

Impact

Vector 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:P CVSS v4.0 Severity and Metrics:

Base Score: 6.90 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:P

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): High
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): High
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): High
Availability (SA): None
Exploit Maturity (E): POC

Base Score 4.0

6.90

Severity 4.0

MEDIUM

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 9.10 CRITICAL
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): High
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): High
Integrity (I): High
Availability (A): High