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LonghornApplication · Linuxfoundation

CVE-2021-36780

HIGH · 8.1 CVSS v3.1 Published 2021-12-17
Fix available
A fix is available. Upgrade to 1.1.3 / 1.2.3 or later.
See remediation →
86/100
Remediation priority · High
No privileges 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 Missing Authentication for Critical Function vulnerability in longhorn of SUSE Longhorn allows attackers to connect to a longhorn-engine replica instance granting it the ability to read and write data to and from a replica that they should not have access to. This issue affects: SUSE Longhorn longhorn versions prior to 1.1.3; longhorn versions prior to 1.2.3v.

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

A Missing Authentication for Critical Function vulnerability in SUSE Longhorn allows unauthenticated attackers to connect to longhorn-engine replica instances, granting unauthorized read and write access to storage data that should be restricted.

MitigationUpgrade Longhorn to version 1.1.3 or later (for the 1.1.x branch) or version 1.2.3 or later (for the 1.2.x branch) to implement proper authentication on replica connections.

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
LonghornApplication
Affected:< 1.1.3>= 1.2.0, < 1.2.3

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

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. Determine Longhorn manager version
    Run kubectl get deployment longhorn-manager -n longhorn-system -o jsonpath='{.spec.template.spec.containers[0].image}' to retrieve the Longhorn manager image tag
    Affected if The returned version is below 1.1.3, or between 1.2.0 and 1.2.2 (inclusive)
  2. Check Longhorn UI version
    Access the Longhorn UI and view the version information, or query the longhorn-manager DaemonSet image in the longhorn-system namespace
    Affected if The displayed version falls within the affected ranges: < 1.1.3 or >= 1.2.0 but < 1.2.3
  3. Verify replica service is accessible
    Check if the longhorn-engine replica service in the longhorn-system namespace has an exposed cluster IP or external IP that could be reached by unauthenticated attackers
    Affected if The replica service is accessible from outside the cluster and the installed Longhorn version is vulnerable

You are affected if Longhorn version is either below 1.1.3 or between 1.2.0 and 1.2.2 inclusive, and replica instances are network-accessible to untrusted users.

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 1.1.3 / 1.2.3 or later
Fixed in 1.1.31.2.3
Interim mitigation

Upgrade Longhorn to version 1.1.3 or later (for the 1.1.x branch) or version 1.2.3 or later (for the 1.2.x branch) to implement proper authentication on replica connections.

Recommended fix High confidence

Longhorn 1.1.3 (for 1.x versions) or Longhorn 1.2.3 (for 1.2.x versions)

  1. 1. Back up all critical data and review Longhorn backup/recovery procedures
  2. 2. Determine current Longhorn version using `longhornctl get version` or kubectl
  3. 3. For versions < 1.1.3: Upgrade directly to Longhorn 1.1.3 or later
  4. 4. For versions >= 1.2.0 but < 1.2.3: Upgrade to Longhorn 1.2.3 or later
  5. 5. For versions >= 1.1.3 and < 1.2.0: Consider upgrading to either 1.1.3+ or 1.2.3+ based on compatibility requirements
  6. 6. Apply upgrade via Helm: `helm upgrade longhorn longhorn/longhorn --namespace longhorn-system` or via kubectl applying the new manifest
  7. 7. Verify upgrade completion: check that all Longhorn components are running and replicas reconnect properly
  8. 8. Test that replica connections require proper authentication

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

Fix this in Longhorn Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2021-36780 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