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Vulnerability · Published Sep 15, 2026 · Assigned by GitHub_M

CVE-2026-55636Capsule: Incomplete fix of CVE-2026-30963: singular/plural typo leaves namespaces/finalize unprotected

Medium 5.7

In plain English

A medium-severity incorrect authorization in capsule from projectcapsule. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.7Medium
Exploit odds (30 days)0.4%top 67.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/projectcapsule/capsule0.13.6GHSA-gwxr-7h77-7777
Gogithub.com/projectcapsule/capsule0.13.6GO-2026-5406

Affected products (as reported)

VendorProductVersions
projectcapsule capsule >= 0.13.0, < 0.13.6

Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:H/A:L

References