CVE-2019-11253
HIGHCVE-2019-11253 is a high-severity (CVSS 7.5) Improper Input Validation vulnerability in k8s.io/kubernetes. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2019-11253 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
XML Entity Expansion and Improper Input Validation in Kubernetes API server
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
Improper input validation in the Kubernetes API server in versions v1.0-1.12 and versions prior to v1.13.12, v1.14.8, v1.15.5, and v1.16.2 allows authorized users to send malicious YAML or JSON payloads, causing the API server to consume excessive CPU or memory, potentially crashing and becoming unavailable. Prior to v1.14.0, default RBAC policy authorized anonymous users to submit requests that could trigger this vulnerability. Clusters upgraded from a version prior to v1.14.0 keep the more permissive policy by default for backwards compatibility.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | k8s.io/kubernetes | ≥ 1.0.0&&< 1.13.12 | 1.13.12 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.14.0&&< 1.14.8 | 1.14.8 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.15.0&&< 1.15.5 | 1.15.5 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.16.0&&< 1.16.2 | 1.16.2 |
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 k8s.io/kubernetes. 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/kubernetes to 1.13.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-11253 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 CVE-2019-11253 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 CVE-2019-11253. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
For Red Hat OpenStack Platform, because kubernetes is not directly used in director-operator, the RHOSP Impact has been moved to Moderate.
Frequently Asked Questions
Is CVE-2019-11253 in your dependencies?
O3 detects CVE-2019-11253 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.