GHSA-33c5-9fx5-fvjm
MEDIUMPrivilege Escalation in Kubernetes
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.
Blast Radius
k8s.io/apimachinery🐹k8s.io/apimachinery🐹k8s.io/apimachinery🐹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
The Kubernetes kube-apiserver in versions v1.6-v1.15, and versions prior to v1.16.13, v1.17.9 and v1.18.7 are vulnerable to an unvalidated redirect on proxied upgrade requests that could allow an attacker to escalate privileges from a node compromise to a full cluster compromise.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | k8s.io/apimachinery | all versions | 0.16.13 |
| 🐹Go | k8s.io/apimachinery | ≥ 0.17.0&&< 0.17.9 | 0.17.9 |
| 🐹Go | k8s.io/apimachinery | ≥ 0.18.0&&< 0.18.7 | 0.18.7 |
| 🐹Go | k8s.io/kubernetes | all versions | 1.16.13 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.17.0&&< 1.17.9 | 1.17.9 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.18.0&&< 1.18.7 | 1.18.7 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
The Kubernetes kube-apiserver in versions v1.6-v1.15, and versions prior…
The Kubernetes kube-apiserver in versions v1.6-v1.15, and versions prior…
The Kubernetes kube-apiserver in versions v1.6-v1.15, and versions prior…
The Kubernetes kube-apiserver in versions v1.6-v1.15, and versions prior…
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for k8s.io/apimachinery. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update k8s.io/apimachinery to 0.16.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-33c5-9fx5-fvjm 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 pinpoints whether GHSA-33c5-9fx5-fvjm is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-33c5-9fx5-fvjm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-33c5-9fx5-fvjm in your dependencies?
O3 detects GHSA-33c5-9fx5-fvjm across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.