Multi-tenancy Framework Vulnerability in Capsule by Project Capsule
CVE-2026-55636

5.7MEDIUM

Key Information:

Vendor

Projectcapsule

Status
Capsule
Vendor
CVE Published:
15 September 2026

What is CVE-2026-55636?

The Capsule framework for Kubernetes has a vulnerability due to misconfigured validating webhooks. Specifically, from versions 0.13.0 to 0.13.6, the configuration allows users with namespaces/finalize RBAC roles to bypass certain security measures. A PUT request sent to /api/v1/namespaces/{namespace}/finalize does not invoke the validating webhook, enabling unauthorized changes to namespace tenant labels. The vulnerability arises from incorrect pluralization rules in API resource handling; a fix has been implemented in version 0.13.6.

Affected Version(s)

capsule >= 0.13.0, < 0.13.6

References

https://github.com/projectcapsule/capsule/security/adviso...
x_refsource_CONFIRM
https://github.com/projectcapsule/capsule/pull/1966
x_refsource_MISC
https://github.com/projectcapsule/capsule/commit/af2f3779...
x_refsource_MISC

CVSS V3.1

Score:
5.7
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
High
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.