CVE-2026-55636— Capsule: Incomplete fix of CVE-2026-30963: singular/plural typo leaves namespaces/finalize unprotected
Quick assessment
Affected
projectcapsule capsule
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Capsule 是一个用于 Kubernetes 的多租户（multi-tenancy）且基于策略的管理框架。在版本 0.13.0 到 0.13.6 期间， 文件错误地将验证 Webhook（validating webhook）配置为使用 规则，而非 Kubernetes 资源的标准名称 。 由于 Kubernetes 中资源的复数形式为 ，单数规则 无法匹配实际资源操作。因此，拥有 RBAC 权限的用户可以向 发送 PUT 请求，而验证 Webhook 不会被触发。攻击者可借此修改命名空间的租户标签（tenan
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I. Basic Information for CVE-2026-55636
Vulnerability Information
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Vulnerability Title
Capsule: Incomplete fix of CVE-2026-30963: singular/plural typo leaves namespaces/finalize unprotected
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:H/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制不正确
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| projectcapsule | capsule | >= 0.13.0, < 0.13.6 | - |
|
II. Public POCs for CVE-2026-55636
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-55636 (1)
Vendor Advisories for CVE-2026-55636 (1)
Vendor Pages for CVE-2026-55636 (1)
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🔗 Release v0.13.6 · projectcapsule/capsule · GitHub x_refsource_MISC
IV. Related Vulnerabilities
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V. Comments for CVE-2026-55636
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