CVE-2019-11251 is a medium-severity (CVSS 5.7) CWE-61 vulnerability in k8s.io/kubernetes. A fix is available for k8s.io/kubernetes — see the affected versions and patch details below.
Kubernetes kubectl cp Vulnerable to Symlink Attack
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2019-11251 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
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 kubectl cp command in versions 1.1-1.12, and versions prior to 1.13.11, 1.14.7, and 1.15.4 allows a combination of two symlinks provided by tar output of a malicious container to place a file outside of the destination directory specified in the kubectl cp invocation. This could be used to allow an attacker to place a nefarious file using a symlink, outside of the destination tree.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | k8s.io/kubernetes | ≥ 1.13.10&&< 1.13.11 | 1.13.11go get k8s.io/kubernetes@v1.13.11 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.14.6&&< 1.14.7 | 1.14.7go get k8s.io/kubernetes@v1.14.7 |
| 🐹Go | k8s.io/kubernetes | ≥ 1.15.3&&< 1.16.0 | 1.16.0go get k8s.io/kubernetes@v1.16.0 |
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 1.13.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-11251 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 did not affect the version of Kubernetes(embedded in heketi) shipped with Red Hat Gluster Storage 3 as it does not include the symlink support for kubectl cp.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Container Platform 3.11 | atomic-openshift-0:3.11.154-1.git.0.7a097ad.el7 | RHSA-2019:3905 |
| Red Hat OpenShift Container Platform 3.9 | atomic-openshift-0:3.9.102-1.git.0.6411f52.el7 | RHSA-2019:3811 |
| Red Hat OpenShift Container Platform 4.1 | openshift-0:4.1.21-201910220952.git.0.493dbf6.el7 | RHSA-2019:3266 |
| Red Hat OpenShift Container Platform 4.1 | openshift4/ose-cli:v4.1.21-201910230924 | RHSA-2019:3267 |
Frequently Asked Questions
Is CVE-2019-11251 in your dependencies?
Find it across Go, including transitive dependencies.