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RancherApplication

CVE-2021-25320

CRITICAL · 9.9 CVSS v3.1 Published 2021-07-15
Fix available
A fix is available. Upgrade to 2.4.16 / 2.5.9 or later.
See remediation →
100/100
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 Rancher, allows users in the cluster to make request to cloud providers by creating requests with the cloud-credential ID. Rancher in this case would attach the requested credentials without further checks This issue affects: Rancher versions prior to 2.5.9; Rancher versions prior to 2.4.16.

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

Rancher versions prior to 2.5.9 and 2.4.16 have an improper access control vulnerability where cluster users can make requests to cloud providers by including a cloud-credential ID in requests. Rancher attaches the requested credentials without performing authorization checks to verify the user has permission to use those credentials.

MitigationUpgrade Rancher to version 2.5.9 or later, or 2.4.16 or later. Review cloud credential usage logs for unauthorized access and rotate any credentials that may have been exposed.

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:< 2.4.16>= 2.5.0, < 2.5.9

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/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. Identify Rancher version
    Navigate to the Rancher UI footer or check the Helm chart values. From the CLI: kubectl get settings server-version -o jsonpath='{.value}' in the local cluster, or check the Rancher pod logs on startup.
    Affected if Version is less than 2.4.16, or greater than or equal to 2.5.0 but less than 2.5.9
  2. Confirm cloud credentials exist
    In Rancher UI, go to Cluster Manager > Cloud Credentials, or run: kubectl get cloudcredentials -A
    Affected if At least one cloud credential is present in the environment
  3. Review API request logs for cloud-credential usage
    Check Rancher audit logs or Kubernetes API server logs for POST/GET requests to /v1/cloudcredentials or requests containing query parameters with cloud-credential IDs. Look for patterns where non-admin users access credential endpoints.
    Affected if Cluster users (non-administrators) have made API calls referencing cloud-credential IDs without corresponding RBAC permissions for those credentials
  4. Verify user role bindings on cloud credentials
    Run: kubectl get roletemplatebindings -A | grep -i cloud to see if cluster users have bindings to cloud credential roles, or check if any user has been granted access to cloud credentials they should not have.
    Affected if Cluster users have unexpected or unauthorized access to cloud credentials through role bindings

Environment is affected if running a vulnerable Rancher version and cluster users have made API requests using cloud-credential IDs they were not explicitly authorized to access.

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 2.4.16 / 2.5.9 or later
Fixed in 2.4.162.5.9
Interim mitigation

Upgrade Rancher to version 2.5.9 or later, or 2.4.16 or later. Review cloud credential usage logs for unauthorized access and rotate any credentials that may have been exposed.

Recommended fix High confidence

Rancher 2.4.16 or Rancher 2.5.9 (depending on your major version branch)

  1. Backup your Rancher installation and etcd data before upgrading
  2. Upgrade Rancher to version 2.4.16 or later if running 2.4.x
  3. OR upgrade Rancher to version 2.5.9 or later if running 2.5.x
  4. Verify the upgrade was successful by checking the Rancher UI and cluster status
  5. Review user access controls and cloud credentials to ensure proper permissions are in place
Caveat Standard Rancher upgrade considerations apply - review release notes for known issues and ensure cluster backup before proceeding

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

Fix this in Rancher Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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-2021-25320 in production — separate from our analysis above.

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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