SEPTEMBER 17, 2026
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Case File

CVE-2026-55636

MEDIUM · CVSS 5.7 EPSS 0.28% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-15 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

The vulnerability affects the Capsule framework for Kubernetes versions 0.13.0 to 0.13.6, where the validating webhook is misconfigured, allowing users with the `namespaces/finalize` RBAC permission to bypass webhook validation and alter namespace tenant labels. This could lead to unauthorized changes in multi-tenant environments, potentially compromising tenant isolation. Kubernetes administrators and security teams should prioritize upgrading to version 0.13.6 or later to mitigate this risk.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-55636
Severity
MEDIUM
CVSS
5.7
EPSS
0.28%
Kubernetes

Original NVD Description

Capsule is a multi-tenancy and policy-based framework for Kubernetes. From 0.13.0 until 0.13.6, charts/capsule/templates/configuration.yaml configures the validating webhook with namespace/finalize instead of the Kubernetes resource name namespaces/finalize. A user with namespaces/finalize RBAC can send a PUT request to /api/v1/namespaces/{namespace}/finalize, and the singular rule never matches the plural resource, so the validating webhook is not invoked and the user can change the namespace tenant label. matchPolicy: Equivalent does not compensate because it handles API group and version equivalence rather than resource-name errors. This vulnerability is fixed in 0.13.6.