kube-apiserver vulnerable to policy bypassGHSA-qc2g-gmh6-95p4
MEDIUMFix: kubernetes/kubernetes#118356GHSA-qc2g-gmh6-95p4 is a medium-severity (CVSS 6.5) Improper Input Validation vulnerability in k8s.io/kubernetes. A fix is available for k8s.io/kubernetes — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-qc2g-gmh6-95p4.
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
k8s.io/kubernetes🐹k8s.io/kubernetes🐹k8s.io/kubernetes🐹k8s.io/kubernetesReal-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
Users may be able to launch containers using images that are restricted by ImagePolicyWebhook when using ephemeral containers. Kubernetes clusters are only affected if the ImagePolicyWebhook admission plugin is used together with ephemeral containers.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | k8s.io/kubernetes | ≥ 1.27.0&&< 1.27.3 | 1.27.3go get k8s.io/kubernetes@v1.27.3 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.26.0&&< 1.26.6 | 1.26.6go get k8s.io/kubernetes@v1.26.6 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.25.0&&< 1.25.11 | 1.25.11go get k8s.io/kubernetes@v1.25.11 |
| 🐹Go | k8s.io/kubernetes | all versions | 1.24.15go get k8s.io/kubernetes@v1.24.15 |
Affected Products
kuberneteskubernetesDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for k8s.io/kubernetes, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update k8s.io/kubernetes to 1.27.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qc2g-gmh6-95p4 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This issue can be mitigated by applying the patch provided for the kube-apiserver component. This patch prevents ephemeral containers from using an image that is restricted by ImagePolicyWebhook. Note: Validation webhooks, (such as Gatekeeper <https://open-policy-agent.github.io/gatekeeper-library/website/validation/allowedrepos> and Kyverno <https://kyverno.io/policies/other/allowed-image-repos/allowed-image-repos/>) can also be used to enforce the same restrictions.Source: Red Hat security advisory for GHSA-qc2g-gmh6-95p4 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Container Platform 4.14 | buildah-1:1.29.1-10.1.rhaos4.14.el8 | RHSA-2023:5009 |
| Red Hat OpenShift Container Platform 4.14 | microshift-0:4.14.0-202310261440.p0.g1586504.assembly.4.14.0.el9 | RHSA-2023:5008 |
Frequently Asked Questions
Is GHSA-qc2g-gmh6-95p4 in your dependencies?
Find it across Go, including transitive dependencies.