CVE-2022-21953 — rancher
HIGHCVE-2022-21953 is a high-severity (CVSS 7.4) CWE-862 vulnerability in github.com/rancher/rancher. A fix is available for github.com/rancher/rancher — see the affected versions and patch details below.
Authenticated user can gain unauthorized shell pod and kubectl access in the local cluster
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-21953.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/rancher/rancher🐹github.com/rancher/rancher🐹github.com/rancher/rancherReal-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
An issue was discovered in Rancher where an authorization logic flaw allows an authenticated user on any downstream cluster to (1) open a shell pod in the Rancher local cluster and (2) have limited kubectl access to it. The expected behavior is that a user does not have such access in the Rancher local cluster unless explicitly granted.
This issue does not allow the user to escalate privileges in the local cluster directly (this would require another vulnerability to be exploited).
The security issue happens in two different ways:
-
Shell pod access - This is when a user opens a shell pod in the Rancher UI to a downstream cluster that the user has permission to access. The web request can be intercepted using the browser's web inspector/network console or a proxy tool to change the shell's destination to the Rancher
localcluster instead of the desired downstream cluster.-
This flaw cannot be exploited to access a downstream cluster that the user has no permissions to.
-
The shell pod runs with a limited non-root user, reducing the severity of this issue. However, even as a non-root user, it is still possible download and run binaries inside the shell pod.
-
The blast radius of this issue can increase based on the configuration of the
localcluster. For example:-
If the
localcluster has unlimited network access, e.g. to the Internet, the user can open a reverse network connection to the shell pod. -
Or access the cloud metadata API of the underlying cloud infrastructure, where the user can extract the credentials associated with the
localcluster and use them to interact with the cloud environment (this will be limited by the permissions granted to the cloud credentials in question). -
Check further recommendations about liming access to the cloud metadata API in Rancher's security best practices.
-
-
-
Kubectl access - When downloading the kubeconfig file of a downstream cluster that the user has access to, the
servercluster address in the kubeconfig file can be changed to point to the Rancherlocalcluster instead of the intended downstream cluster.-
This can also be achieved by crafting a kubeconfig using a Rancher token instead of using the kubeconfig from an active cluster.
-
This flaw cannot be exploited to access a downstream cluster that the user has no permissions to.
-
Notes:
- Rancher
localcluster means the cluster where Rancher is installed. It is named aslocalinside the list of clusters in the Rancher UI. - Audit logs in Rancher can be used to identify possible abuses of this issue, by tracking API requests to the user ID of the user that performed the action. API audit logs can be enabled as described in the documentation when set to level
1or above.
Workarounds
There is no workaround or direct mitigation besides updating to a patched Rancher version.
Patches
Patched versions include releases 2.5.17, 2.6.10, 2.7.1 and later versions.
For more information
If you have any questions or comments about this advisory:
- Reach out to SUSE Rancher Security team for security related inquiries.
- Open an issue in Rancher repository.
- Verify our support matrix and product support lifecycle.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/rancher/rancher | ≥ 2.5.0&&< 2.5.17 | 2.5.17go get github.com/rancher/rancher@v2.5.17 |
| 🐹Go | github.com/rancher/rancher | ≥ 2.6.0&&< 2.6.10 | 2.6.10go get github.com/rancher/rancher@v2.6.10 |
| 🐹Go | github.com/rancher/rancher | ≥ 2.7.0&&< 2.7.1 | 2.7.1go get github.com/rancher/rancher@v2.7.1 |
Affected Products
ranchersuseDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/rancher/rancher, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/rancher/rancher to 2.5.17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-21953 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.
Frequently Asked Questions
Is CVE-2022-21953 in your dependencies?
Find it across Go, including transitive dependencies.