Exposure of repository credentials to external third-party sources in Rancher

Exploitation

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

CVSS

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

EPSS

• CVE-2021-36778: 0.76% estimated exploitation activity in the next 30 days; percentile 55.21 (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 issue only happens when the user configures access credentials to a private repository in Rancher inside Apps & Marketplace Repositories. It affects Rancher versions 2.5.0 up to and including 2.5.11 and from 2.6.0 up to and including 2.6.2. An insufficient check of the same-origin policy when downloading Helm charts from a configured private repository can lead to exposure of the repository credentials to a third-party provider. This exposure happens when the private repository: 1. Does an HTTP redirect to a third-party repository or external storage provider. 2. Downloads an icon resource for the chart hosted on a third-party provider. The address of the private repository is not leaked, only the credentials are leaked in the HTTP Authorization header in base64 format. With the patched versions, the default behavior now is to only send the private repository credentials when subdomain or domain hostname match when following the redirect or downloading external resources.…

Published by the source

2 May 2022, 19:33 UTC

Last modified by the source

28 Jan 2023, 05:07 UTC

Source last checked

26 Oct 2026, 14:54 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4fc7-hc63-7fjg

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# Patch Next advisory brief: CVE-2021-36778

Advisory: Exposure of repository credentials to external third-party sources in Rancher
IDs: CVE-2021-36778, GHSA-4fc7-hc63-7fjg
Record: https://patchnext.com/advisories/cve-2021-36778 (revision 1, source checked 26 Oct 2026, 14:54 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.3)
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 2.6.3, 2.5.12. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/rancher/rancher: affected >= 2.6.0, < 2.6.3; >= 2.5.0, < 2.5.12; fixed in 2.5.12, 2.6.3

## 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-4fc7-hc63-7fjg (GitHub-reviewed advisory GHSA-4fc7-hc63-7fjg lists affected ranges: Go github.com/rancher/rancher >=2.6.0 =2.5.0 <2.5.12)

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