Write access to the catalog for any user when restricted-admin role is enabled in Rancher

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2021-4200: 0.62% estimated exploitation activity in the next 30 days; percentile 49.94 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact This vulnerability only affects customers using the restricted-admin role in Rancher. For this role to be active, Rancher must be bootstrapped with the environment variable CATTLERESTRICTEDDEFAULTADMIN=true or the configuration flag restrictedAdmin=true. A flaw was discovered in Rancher versions from 2.5.0 up to and including 2.5.12 and from 2.6.0 up to and including 2.6.3 where the global-data role in cattle-global-data namespace grants write access to the Catalogs. Since each user with any level of catalog access was bound to the global-data role, this grants write access to templates (CatalogTemplates) and template versions (CatalogTemplateVersions) for any user with any level of catalog access. New users created in Rancher are by default assigned to the user role (standard user), which is not designed to grant write catalog access. This vulnerability effectively elevates the privilege of any user to write access for the catalog template and catalog template version…

Published by the source

2 May 2022, 19:26 UTC

Last modified by the source

3 Feb 2023, 05:04 UTC

Source last checked

26 Oct 2026, 14:55 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-hx8w-ghh8-r4xf

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# Patch Next advisory brief: CVE-2021-4200

Advisory: Write access to the catalog for any user when restricted-admin role is enabled in Rancher
IDs: CVE-2021-4200, GHSA-hx8w-ghh8-r4xf
Record: https://patchnext.com/advisories/cve-2021-4200 (revision 1, source checked 26 Oct 2026, 14:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/rancher/rancher 2.6.4, 2.5.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/rancher/rancher: affected >= 2.6.0, < 2.6.4; >= 2.5.0, < 2.5.13; fixed in 2.5.13, 2.6.4

## Suggested inspection (read-only)
- Go github.com/rancher/rancher: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/rancher/rancher.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-hx8w-ghh8-r4xf (GitHub-reviewed advisory GHSA-hx8w-ghh8-r4xf lists affected ranges: Go github.com/rancher/rancher >=2.6.0 =2.5.0 <2.5.13)

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