GHSA-g7j7-h4q8-8w2f CVE-2021-36782

Rancher API and cluster.management.cattle.io object vulnerable to plaintext storage and exposure of credentials

Critical Go

Severity: 9.9 / 10; Critical · CVSS 3.1
Exploit chance (EPSS): 4.17%; Chance of exploitation in the next 30 days. Higher than 90.90% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-312 Cleartext Storage of Sensitive Information
Fix: 2.5.16; Upgrade github.com/rancher/rancher to this version or later

Description

Impact

An issue was discovered in Rancher versions up to and including 2.5.15 and 2.6.6 where sensitive fields, like passwords, API keys and Rancher's service account token (used to provision clusters), were stored in plaintext directly on Kubernetes objects like Clusters, for example cluster.management.cattle.io. Anyone with read access to those objects in the Kubernetes API could retrieve the plaintext version of those sensitive data.

The exposed credentials are visible in Rancher to authenticated Cluster Owners, Cluster Members, Project Owners, Project Members and User Base on the endpoints:

/v1/management.cattle.io.catalogs
/v1/management.cattle.io.cluster
/v1/management.cattle.io.clustertemplates
/v1/management.cattle.io.notifiers
/v1/project.cattle.io.sourcecodeproviderconfig
/k8s/clusters/local/apis/management.cattle.io/v3/catalogs
/k8s/clusters/local/apis/management.cattle.io/v3/clusters
/k8s/clusters/local/apis/management.cattle.io/v3/clustertemplates
/k8s/clusters/local/apis/management.cattle.io/v3/notifiers
/k8s/clusters/local/apis/project.cattle.io/v3/sourcecodeproviderconfigs

Sensitive fields are now stripped from Clusters and other objects and moved to a Secret before the object is stored. The Secret is retrieved when the credential is needed. For objects that existed before this security fix, a one-time migration happens on startup.

Important:

The exposure of Rancher's serviceAccountToken allows any standard user to escalate its privileges to cluster administrator in Rancher.
For the exposure of credentials not related to Rancher, the final impact severity for confidentiality, integrity and availability is dependent on the permissions that the leaked credentials have on their own services.

The fields that have been addressed by this security fix are:

Notifier.SMTPConfig.Password
Notifier.WechatConfig.Secret
Notifier.DingtalkConfig.Secret
Catalog.Spec.Password
SourceCodeProviderConfig.GithubPipelineConfig.ClientSecret
SourceCodeProviderConfig.GitlabPipelineConfig.ClientSecret
SourceCodeProviderConfig.BitbucketCloudPipelineConfig.ClientSecret
SourceCodeProviderConfig.BitbucketServerPipelineConfig.PrivateKey
Cluster.Spec.RancherKubernetesEngineConfig.BackupConfig.S3BackupConfig.SecretKey
Cluster.Spec.RancherKubernetesEngineConfig.PrivateRegistries.Password
Cluster.Spec.RancherKubernetesEngineConfig.Network.WeaveNetworkProvider.Password
Cluster.Spec.RancherKubernetesEngineConfig.CloudProvider.VsphereCloudProvider.Global.Password
Cluster.Spec.RancherKubernetesEngineConfig.CloudProvider.VsphereCloudProvider.VirtualCenter.Password
Cluster.Spec.RancherKubernetesEngineConfig.CloudProvider.OpenstackCloudProvider.Global.Password
Cluster.Spec.RancherKubernetesEngineConfig.CloudProvider.AzureCloudProvider.AADClientSecret
Cluster.Spec.RancherKubernetesEngineConfig.CloudProvider.AzureCloudProvider.AADClientCertPassword
Cluster.Status.ServiceAccountToken
ClusterTemplate.Spec.ClusterConfig.RancherKubernetesEngineConfig.PrivateRegistries.Password
ClusterTemplate.Spec.ClusterConfig.RancherKubernetesEngineConfig.Network.WeaveNetworkProvider.Password
ClusterTemplate.Spec.ClusterConfig.RancherKubernetesEngineConfig.CloudProvider.VsphereCloudProvider.Global.Password
ClusterTemplate.Spec.ClusterConfig.RancherKubernetesEngineConfig.CloudProvider.VsphereCloudProvider.VirtualCenter.Password
ClusterTemplate.Spec.ClusterConfig.RancherKubernetesEngineConfig.CloudProvider.OpenstackCloudProvider.Global.Password
ClusterTemplate.Spec.ClusterConfig.RancherKubernetesEngineConfig.CloudProvider.AzureCloudProvider.AADClientSecret
ClusterTemplate.Spec.ClusterConfig.RancherKubernetesEngineConfig.CloudProvider.AzureCloudProvider.AADClientCertPassword

Patches

Patched versions include releases 2.5.16, 2.6.7 and later versions.

After upgrading to a patched version, it is important to check for the SecretsMigrated condition on Clusters, ClusterTemplates, and Catalogs to confirm when secrets have been fully migrated off of those objects and the objects scoped within them (Notifiers and SourceCodeProviderConfigs).

Workarounds

Limit access in Rancher to trusted users. There is not a direct mitigation besides upgrading to the patched Rancher versions.

Important:

It is highly advised to rotate Rancher's serviceAccountToken. This rotation is not done by the version upgrade. Please see the helper script below.
The local and downstream clusters should be checked for potential unrecognized services (pods), users and API keys.
It is recommended to review for potential leaked credentials in this scenario, that are not directly related to Rancher, and to change them if deemed necessary.

The script available in rancherlabs/support-tools/rotate-tokens repository can be used as a helper to rotate the service account token (used to provision clusters). The script requires a valid Rancher API token, kubectl access to the local cluster and the jq command.

Credits

We would like to recognize and appreciate Florian Struck (from Continum AG) and Marco Stuurman (from Shock Media B.V.) for the responsible disclosure of this security issue.

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 versions

Go

Package	Vulnerable	Fixed in
github.com/rancher/rancher	`>= 2.5.0, < 2.5.16`	`2.5.16`
github.com/rancher/rancher	`>= 2.6.0, < 2.6.7`	`2.6.7`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

github.com/rancher/rancher Go → `2.5.16`

go

go get github.com/rancher/rancher@v2.5.16 && go mod tidy

Severity breakdown

CVSS 3.1 9.9

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: High
Availability: High

Weakness

CWE-312: Cleartext Storage of Sensitive Information

The product stores sensitive information in cleartext within a resource that might be accessible to another control sphere.

How to prevent it

Implementation, System Configuration, Operation: When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to encrypt the data at rest. [REF-1297] [REF-1299] [REF-1301]
Implementation, System Configuration, Operation: In some systems/environments such as cloud, the use of "double encryption" (at both the software and hardware layer) might be required, and the developer might be solely responsible for both layers, instead of shared responsibility with the administrator of the broader system/environment.

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2021-36782

Packages

github.com/rancher/rancher

Timeline

Sep 7, 2022 Published
Jul 8, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-4j6x-2764-m8gh Rancher has over-inclusive team membership expansion in GitHub App authentication provider	High	Also affects github.com/rancher/rancher
GHSA-vx8h-4prv-g744 Rancher has Privilege Escalation from Project Owner to Host	High	Also affects github.com/rancher/rancher
GHSA-mhc6-2gfq-xx62 Rancher vulnerable to command injection through unsanitized YAML parameter	Critical	Also affects github.com/rancher/rancher
GHSA-5v3h-x4wf-5c35 Rancher Extensions have arbitrary file access via path traversal	High	Also affects github.com/rancher/rancher
GHSA-gqf8-rvrh-g7w6 Rancher cloud credentials can be used through proxy API by users without access	Critical	Also affects github.com/rancher/rancher
GHSA-hwm2-4ph6-w6m5 Rancher's restricted PodSecurityPolicy does not prevent containers from running as a privileged user	High	Also affects github.com/rancher/rancher
GHSA-mc24-7m59-4q5p Rancher CLI skips TLS verification on Rancher CLI login command	Medium	Also affects github.com/rancher/rancher
GHSA-mw39-9qc2-f7mg Rancher exposes sensitive information through audit logs	Medium	Also affects github.com/rancher/rancher

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