CVE-2023-46254 is a medium-severity (CVSS 4.3) Information Exposure vulnerability in github.com/projectcapsule/capsule. A fix is available for github.com/projectcapsule/capsule — see the affected versions and patch details below.
Service accounts can see namespaces of other tenants in capsule-proxy
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/projectcapsule/capsule🐹github.com/projectcapsule/capsule-proxyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/projectcapsule/capsule | all versions | 0.4.5go get github.com/projectcapsule/capsule@v0.4.5 |
| 🐹Go | github.com/projectcapsule/capsule-proxy | all versions | 0.4.5go get github.com/projectcapsule/capsule-proxy@v0.4.5 |
Affected Products
capsuleclastixcapsule-proxyclastixDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/projectcapsule/capsule, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/projectcapsule/capsule to 0.4.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-46254 is resolved across your whole dependency graph.
Workarounds
Close the privilege gap rather than the entry point: audit which accounts, roles and service identities can reach the affected operation, drop the component to the least privilege it actually needs, and review file and directory permissions created by earlier installs — a default left in place is what makes this reachable.
Frequently Asked Questions
Is CVE-2023-46254 in your dependencies?
Find it across Go, including transitive dependencies.