containerd-shim API Exposed to Host Network ContainersGHSA-36xw-fx78-c5r4
MEDIUMFix: containerd/containerd@4a4bb85GHSA-36xw-fx78-c5r4 is a medium-severity (CVSS 5.2) CWE-669 vulnerability in github.com/containerd/containerd. 2 public exploit references exist, so weaponization risk is real. A fix is available for github.com/containerd/containerd — see the affected versions and patch details below.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-36xw-fx78-c5r4 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/containerd/containerd🐹github.com/containerd/containerdReal-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
Impact
Access controls for the shim’s API socket verified that the connecting process had an effective UID of 0, but did not otherwise restrict access to the abstract Unix domain socket. This would allow malicious containers running in the same network namespace as the shim, with an effective UID of 0 but otherwise reduced privileges, to cause new processes to be run with elevated privileges.
Specific Go Packages Affected
github.com/containerd/containerd/cmd
Patches
This vulnerability has been fixed in containerd 1.3.9 and 1.4.3. Users should update to these versions as soon as they are released. It should be noted that containers started with an old version of containerd-shim should be stopped and restarted, as running containers will continue to be vulnerable even after an upgrade.
Workarounds
If you are not providing the ability for untrusted users to start containers in the same network namespace as the shim (typically the "host" network namespace, for example with docker run --net=host or hostNetwork: true in a Kubernetes pod) and run with an effective UID of 0, you are not vulnerable to this issue.
If you are running containers with a vulnerable configuration, you can deny access to all abstract sockets with AppArmor by adding a line similar to deny unix addr=@**, to your policy.
It is best practice to run containers with a reduced set of privileges, with a non-zero UID, and with isolated namespaces. The containerd maintainers strongly advise against sharing namespaces with the host. Reducing the set of isolation mechanisms used for a container necessarily increases that container's privilege, regardless of what container runtime is used for running that container.
Credits
The containerd maintainers would like to thank Jeff Dileo of NCC Group for responsibly disclosing this issue in accordance with the containerd security policy and for reviewing the patch.
For more information
If you have any questions or comments about this advisory:
- Open an issue
- Email us at [email protected] if you think you’ve found a security bug.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/containerd/containerd | all versions | 1.3.9go get github.com/containerd/containerd@v1.3.9 |
| 🐹Go | github.com/containerd/containerd | ≥ 1.4.0&&< 1.4.3 | 1.4.3go get github.com/containerd/containerd@v1.4.3 |
Affected Products
debian linuxdebianfedorafedoraprojectcontainerdlinuxfoundationResearch 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/containerd/containerd, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/containerd/containerd to 1.3.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-36xw-fx78-c5r4 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
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.
* The container runtime in OpenShift Container Platform 4 is cri-o which is not affected by this flaw. It doesn't make use of abstract unix sockets like containerd, which lead to this vulnerability being possible. * Red Hat Advanced Cluster Management for Kubernetes is not affected by this flaw. While containerd is…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenStack Platform 16.2 | rhosp-rhel8-tech-preview/osp-director-operator:1.2.3-2 | RHSA-2022:2183 |
Frequently Asked Questions
Is GHSA-36xw-fx78-c5r4 in your dependencies?
Find it across Go, including transitive dependencies.