CVE-2021-36783: Github.com/rancher/rancher Rancher Doesn't Properly Sanitize Credentials Vulnerability

CRITICAL
Advisory Identifier: GHSA-8w87-58w6-hfv8
CVSS 9.9
CWE-312 CWE-522 CWE-200
Published
Advisory Summary

CVE-2021-36783 is a CRITICAL (CVSS 9.9) rancher doesn't properly sanitize credentials vulnerability (CWE-312: Cleartext Storage of Sensitive Information) affecting Github.com/rancher/rancher libraries in the Go ecosystem. The issue involves rancher doesn't properly sanitize credentials in cluster template answers. Remediation is available by upgrading affected packages to version 2.5.13, 2.6.4.

CVE-2021-36783 at a Glance

CVE Identifier CVE-2021-36783
GHSA Identifier GHSA-8w87-58w6-hfv8
Severity CRITICAL
CVSS v3.1 Base Score 9.9
CWE Classification CWE-312: Cleartext Storage of Sensitive Information
Affected Product Github.com/rancher/rancher
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 9.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2021-36783

To remediate this vulnerability, upgrade all affected Github.com/rancher/rancher dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/rancher/rancher fixed: 2.5.13
Upgrade github.com/rancher/rancher to 2.5.13
github.com/rancher/rancher fixed: 2.6.4
Upgrade github.com/rancher/rancher to 2.6.4
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for github.com/rancher/rancher

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-36783, inspect your project dependencies for Github.com/rancher/rancher:

inspect dependencies for github.com/rancher/rancher

Analyze the terminal output to locate any version of Github.com/rancher/rancher in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.5.13), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-312: Cleartext Storage of Sensitive Information, where the product stores sensitive information in cleartext within a resource that might be accessible to another control sphere. In Github.com/rancher/rancher, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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: * Reach out to [SUSE Rancher Security team](https://github.com/rancher/rancher/security/policy) for security related inquiries. * Open an issue in [Rancher](https://github.com/rancher/rancher/issues/new/choose) repository. * Verify our [support matrix](https://www.suse.com/suse-rancher/support-matrix/all-supported-versions/) and [product support lifecycle](https://www.suse.com/lifecycle/).

CVE-2021-36783 Affected Github.com/rancher/rancher Versions

2 component(s)
Fixed Versions:
2.5.132.6.4
Product / Package Ecosystem Affected Versions Fixed Version
github.com/rancher/rancher
Go
≥ 2.5.0
< 2.5.13
2.5.13
github.com/rancher/rancher
Go
≥ 2.6.0
< 2.6.4
2.6.4

References

Frequently Asked Questions

What is CVE-2021-36783?
CVE-2021-36783 is a security vulnerability in Github.com/rancher/rancher involving Rancher doesn't properly sanitize credentials in cluster template answers under CWE-312: Cleartext Storage of Sensitive Information.
Which Github.com/rancher/rancher versions are affected?
Affected versions include releases prior to 2.5.13, 2.6.4 across affected packages: github.com/rancher/rancher.
What version fixes CVE-2021-36783?
Upgrading to 2.5.13, 2.6.4 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/rancher/rancher affected?
Yes, github.com/rancher/rancher is affected in releases prior to 2.5.13, 2.6.4. Upgrade your dependency to 2.5.13, 2.6.4 or later.
What is the CVSS score of CVE-2021-36783?
CVE-2021-36783 has a CVSS v3.1 base score of 9.9 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2021-36783?
CVE-2021-36783 is classified under 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 can I check Go dependencies for CVE-2021-36783?
Run the dependency tree command: 'inspect dependencies for github.com/rancher/rancher'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8w87-58w6-hfv8",
  "modified" : "2026-03-03T14:49:34Z",
  "published" : "2026-03-03T14:49:34Z",
  "aliases" : [ "CVE-2021-36783" ],
  "summary" : "Rancher doesn't properly sanitize credentials in cluster template answers",
  "details" : "### Impact\n\nIt 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.\n\nThe 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`.\n\nSensitive 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.\n\n**Important:**\n- It is highly advised to review for potential leaked credentials in this scenario, and to change them if deemed necessary.\n- The final impact severity for confidentiality, integrity and availability is dependent on the permissions that the leaked credentials have on their own services.\n\n### Patches\nPatched versions include releases 2.5.13, 2.6.4 and later versions.\n\n### Workarounds\nLimit access in Rancher to trusted users. There is not a direct mitigation besides upgrading to the patched Rancher versions.\n\n**Important:** It is highly advised to review for potential leaked credentials in this scenario, and to change them if deemed necessary.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Reach out to [SUSE Rancher Security team](https://github.com/rancher/rancher/security/policy) for security related inquiries.\n* Open an issue in [Rancher](https://github.com/rancher/rancher/issues/new/choose) repository.\n* Verify our [support matrix](https://www.suse.com/suse-rancher/support-matrix/all-supported-versions/) and [product support lifecycle](https://www.suse.com/lifecycle/).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/rancher/rancher"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.5.0"
      }, {
        "fixed" : "2.5.13"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.5.12"
    }
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/rancher/rancher"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.6.0"
      }, {
        "fixed" : "2.6.4"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.6.3"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/rancher/rancher/security/advisories/GHSA-8w87-58w6-hfv8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-36783"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.suse.com/show_bug.cgi?id=1193990"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rancher/rancher"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-312", "CWE-522" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-03T14:49:34Z",
    "nvd_published_at" : "2022-09-07T09:15:00Z"
  }
}