CVE-2023-46254: capsule-proxy is a reverse proxy for Capsule kubernetes multi-tenancy framework. A bug in the RoleBinding reflector used by `capsule-proxy` gives Serv...

Description

capsule-proxy is a reverse proxy for Capsule kubernetes multi-tenancy framework. A bug in the RoleBinding reflector used by `capsule-proxy` gives ServiceAccount tenant owners the right to list Namespaces of other tenants backed by the same owner kind and name. For example consider two tenants `solar` and `wind`. Tenant `solar`, owned by a ServiceAccount named `tenant-owner` in the Namespace `solar`. Tenant `wind`, owned by a ServiceAccount named `tenant-owner` in the Namespace `wind`. The Tenant owner `solar` would be able to list the namespaces of the Tenant `wind` and vice-versa, although this is not correct. The bug introduces an exfiltration vulnerability since allows the listing of Namespace resources of other Tenants, although just in some specific conditions: 1. `capsule-proxy` runs with the `--disable-caching=false` (default value: `false`) and 2. Tenant owners are ServiceAccount, with the same resource name, but in different Namespaces. This vulnerability doesn't allow any privilege escalation on the outer tenant Namespace-scoped resources, since the Kubernetes RBAC is enforcing this. This issue has been addressed in version 0.4.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

0.41%

33.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-200

Affected Software

Vendor	Product	Versions
Clastix	Capsule	< 0.4.5
Clastix	Capsule-Proxy	< 0.4.5

References

Timeline

Published: Nov 6, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-46254?

capsule-proxy is a reverse proxy for Capsule kubernetes multi-tenancy framework. A bug in the RoleBinding reflector used by `capsule-proxy` gives ServiceAccount tenant owners the right to list Namespaces of other tenants backed by the same owner kind and name. For example consider two tenants `solar` and `wind`. Tenant `solar`, owned by a ServiceAccount named `tenant-owner` in the Namespace `solar`. Tenant `wind`, owned by a ServiceAccount named `tenant-owner` in the Namespace `wind`. The Tenant owner `solar` would be able to list the namespaces of the Tenant `wind` and vice-versa, although this is not correct. The bug introduces an exfiltration vulnerability since allows the listing of Namespace resources of other Tenants, although just in some specific conditions: 1. `capsule-proxy` runs with the `--disable-caching=false` (default value: `false`) and 2. Tenant owners are ServiceAccount, with the same resource name, but in different Namespaces. This vulnerability doesn't allow any privilege escalation on the outer tenant Namespace-scoped resources, since the Kubernetes RBAC is enforcing this. This issue has been addressed in version 0.4.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

How severe is CVE-2023-46254?

CVE-2023-46254 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.41% probability of exploitation in the next 30 days.

How do I fix CVE-2023-46254?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.