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RancherApplication

CVE-2021-36776

HIGH · 8.8 CVSS v3.1 Published 2022-04-04
Fix available
A fix is available. Upgrade to 2.5.10 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A Improper Access Control vulnerability in SUSE Rancher allows remote attackers impersonate arbitrary users. This issue affects: SUSE Rancher Rancher versions prior to 2.5.10.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is an improper access control vulnerability in SUSE Rancher that allows remote attackers to impersonate arbitrary users by bypassing authentication controls. The vulnerability exists in versions prior to 2.5.10 and enables unauthorized access to the Rancher management platform by spoofing user identities.

MitigationUpgrade SUSE Rancher to version 2.5.10 or later to remediate this vulnerability. Prior to upgrading, assess current user access patterns and implement additional monitoring for suspicious authentication events.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
RancherApplication
Affected:< 2.5.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Rancher is installed
    Run 'kubectl get pods -n cattle-system' or check for Rancher-related namespaces and workloads in your cluster
    Affected if Rancher is not present in the environment (not affected)
  2. Identify Rancher version
    Execute 'kubectl get rancher --namespace cattle-system -o jsonpath="{.items[0].status.version}"' or access Rancher UI > About Rancher to view the installed version
    Affected if Unable to determine the Rancher version (further investigation needed)
  3. Compare version to affected range
    Check if the installed version is semantically less than 2.5.10 (e.g., 2.5.9, 2.5.8, 2.4.x, 2.3.x, etc.)
    Affected if Installed version is < 2.5.10 (affected)
  4. Confirm authentication module is enabled
    Rancher authentication (local or external) is enabled by default; verify via Rancher UI > Users & Authentication > Providers
    Affected if Authentication providers are configured (the bypass vulnerability applies to authenticated endpoints)

You are affected if Rancher is installed and the running version is prior to 2.5.10, as the authentication bypass allows impersonation of any user including those defined in local or external auth providers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.5.10 or later
Fixed in 2.5.10
Interim mitigation

Upgrade SUSE Rancher to version 2.5.10 or later to remediate this vulnerability. Prior to upgrading, assess current user access patterns and implement additional monitoring for suspicious authentication events.

Recommended fix High confidence

Rancher 2.5.10

  1. Review the Rancher upgrade documentation for your deployment type (Docker or Kubernetes)
  2. Take a full backup of your Rancher server data and etcd snapshot before upgrading
  3. For Docker deployment: Stop the current Rancher container, then start a new container with the new image tag (rancher/rancher:v2.5.10)
  4. For Kubernetes deployment: Update the Rancher Helm chart to the version corresponding to 2.5.10 and run helm upgrade
  5. After upgrade, verify all services are running and test user authentication to confirm the fix is effective
  6. Review release notes for 2.5.10 to check for any required post-upgrade migrations
Caveat Review 2.5.10 release notes for any breaking changes or required migration steps before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Rancher Scoped from the published advisory
  • Consultation8.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,680
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,088.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-36776 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data