dbcve.org
Clustered Data OntapOperating system · Netapp

CVE-2021-27001

MEDIUM · 5.5 CVSS v3.1 Published 2021-10-19
Fix available
A fix is available. Upgrade to after 9.4 or later.
See remediation →
57/100
Remediation priority · Elevated
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
Clustered Data ONTAP versions 9.x prior to 9.5P18, 9.6P16, 9.7P16, 9.8P7 and 9.9.1P2 are susceptible to a vulnerability which could allow an authenticated privileged local attacker to arbitrarily modify Compliance-mode WORM data prior to the end of the retention period.

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 · moderate confidence

In Clustered Data ONTAP versions 9.x prior to 9.5P18, 9.6P16, 9.7P16, 9.8P7 and 9.9.1P2, an authenticated privileged local attacker can bypass WORM (Write Once Read Many) compliance controls to arbitrarily modify Compliance-mode WORM data before its scheduled retention period expires, violating data immutability guarantees.

MitigationApply the vendor-supplied patches (9.5P18, 9.6P16, 9.7P16, 9.8P7, or 9.9.1P2 or later) to affected ONTAP installations. After patching, audit WORM data integrity to ensure no unauthorized modifications occurred.

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
Clustered Data OntapOperating system
Affected:>= 9.0, <= 9.4= 9.5= 9.6= 9.7= 9.8= 9.9.1

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

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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. Check ONTAP version
    Run the command 'version' in the ONTAP CLI (system node run -node * -command version) or view the version in System Manager under Cluster > Overview
    Affected if The version is 9.0 through 9.4, 9.5 (any patch before P18), 9.6 (any patch before P16), 9.7 (any patch before P16), 9.8 (any patch before P7), or 9.9.1 (any patch before P2)
  2. Confirm WORM Compliance is in use
    Check if Compliance-mode WORM files orSnapLock volumes exist using 'volume show -fields snaplock-type' or 'vserver show' for SnapLock configuration
    Affected if SnapLock volumes with compliance-mode are configured or WORM files with scheduled retention periods exist on the system
  3. Verify write access controls
    Review audit logs for any write operations on WORM-protected files using 'volume audit show' or check storage console logs for write events on SnapLock volumes
    Affected if Write operations occurred on Compliance-mode WORM files before their scheduled retention expiry, indicating potential bypass

You are affected if your Clustered Data ONTAP version falls within the unpatched ranges AND you have Compliance-mode WORM or SnapLock volumes in use, with evidence of unauthorized writes to immutability-protected data.

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 a release after 9.4
Interim mitigation

Apply the vendor-supplied patches (9.5P18, 9.6P16, 9.7P16, 9.8P7, or 9.9.1P2 or later) to affected ONTAP installations. After patching, audit WORM data integrity to ensure no unauthorized modifications occurred.

Recommended fix High confidence

Upgrade to 9.5P18 (for 9.5), 9.6P16 (for 9.6), 9.7P16 (for 9.7), 9.8P7 (for 9.8), or 9.9.1P2 (for 9.9.1)

  1. 1. Identify the current Clustered Data ONTAP version by running: `version`
  2. 2. Determine the appropriate target patch version based on your current major version: 9.5P18, 9.6P16, 9.7P16, 9.8P7, or 9.9.1P2
  3. 3. Review NetApp's upgrade pre-check requirements and ensure adequate storage space for the upgrade
  4. 4. Create a backup or snapshot of the system as a precaution before upgrading
  5. 5. Download the appropriate patch from the NetApp Support Site
  6. 6. Use the `system node image modify` and `system node upgrade` commands, or perform the upgrade via System Manager
  7. 7. Verify the upgrade completed successfully by checking the version with `version`
  8. 8. Confirm the WORM compliance functionality is working correctly
Caveat Upgrading patch versions in NetApp ONTAP is generally low-risk but always review release notes for any configuration changes or deprecated features

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

Fix this in Clustered Data Ontap Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

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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-2021-27001 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