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Rancher doesn't properly sanitize credentials in cluster template answers

Critical severity GitHub Reviewed Published Aug 19, 2022 in rancher/rancher • Updated Mar 3, 2026

Package

gomod github.com/rancher/rancher (Go)

Affected versions

>= 2.5.0, <= 2.5.12
>= 2.6.0, <= 2.6.3

Patched versions

2.5.13
2.6.4

Description

Impact

It was discovered that in Rancher versions up to and including 2.5.12 and 2.6.3 there is a failure to properly sanitize credentials in cluster template answers. This failure can lead to plaintext storage and exposure of credentials, passwords and API tokens.

The exposed credentials are visible in Rancher to authenticated Cluster Owners, Cluster Members, Project Owners and Project Members on the endpoints /v1/management.cattle.io.clusters, /v3/clusters and /k8s/clusters/local/apis/management.cattle.io/v3/clusters.

Sensitive fields are now stripped from Clusters objects before the object is stored. For objects that existed before this security fix, a one-time migration happens on startup.

Important:

  • It is highly advised to review for potential leaked credentials in this scenario, and to change them if deemed necessary.
  • The final impact severity for confidentiality, integrity and availability is dependent on the permissions that the leaked credentials have on their own services.

Patches

Patched versions include releases 2.5.13, 2.6.4 and later versions.

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 review for potential leaked credentials in this scenario, and to change them if deemed necessary.

For more information

If you have any questions or comments about this advisory:

References

@rmweir rmweir published to rancher/rancher Aug 19, 2022
Published by the National Vulnerability Database Sep 7, 2022
Published to the GitHub Advisory Database Mar 3, 2026
Reviewed Mar 3, 2026
Last updated Mar 3, 2026

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

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

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(65th percentile)

Weaknesses

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

Cleartext Storage of Sensitive Information

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

Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval. Learn more on MITRE.

CVE ID

CVE-2021-36783

GHSA ID

GHSA-8w87-58w6-hfv8

Source code

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