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🛡️ CVE-2021-36783 — rancher

🔴 CVSS 9.5 — Critical ✅ No Known Exploit CWE-200 OSV
9.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Rancher doesn't properly sanitize credentials in cluster template answers

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/).

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2021-36783 is classified as CWE-200: Exposure of Sensitive Information. Information that should stay internal is disclosed to someone who is not authorised to see it.

Affected software

CVE-2021-36783 is recorded against 1 package.

  • github.com/rancher/rancher

Timeline and source

Published on 3 March 2026 and last revised on 8 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
nvd.nist.gov (Advisory)
bugzilla.suse.com (Web)
github.com (Package)

Other advisories for this package

github.com/rancher/rancher has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-200: Exposure of Sensitive Information) in other software:

Details

Severity CRITICAL
CVSS Score 9.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE CWE-200
Public Exploit ✅ No
Source OSV
Published 2026-03-03
Updated 2026-08-20
Modified 2026-07-08
Fix URL N/A

Affected Packages

Software From version Fixed in
github.com/rancher/rancher — —

Similar Threats

Exploit Protection

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