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CpanelApplication

CVE-2020-10121

CRITICAL · 9.8 CVSS v3.1 Published 2020-03-17
Fix available
A fix is available. Upgrade to 78.0.45 / 84.0.20 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable 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
cPanel before 84.0.20 allows a demo account to achieve code execution via PassengerApps APIs (SEC-546).

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

cPanel versions before 84.0.20 contain a vulnerability in the PassengerApps APIs that allows demo accounts to achieve arbitrary code execution. The issue stems from insufficient access controls on the Passenger application management APIs, permitting a low-privilege demo user to execute commands on the underlying system.

MitigationUpgrade cPanel to version 84.0.20 or later. If immediate patching is not possible, consider restricting or disabling demo accounts and reviewing API access controls.

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
CpanelApplication
Affected:>= 77.9999.110, < 78.0.45>= 83.9999.115, < 84.0.20

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Identify installed cPanel version
    Run '/usr/local/cpanel/cpanel -V' or check the cPanel version in WHM under 'Server Information' or 'cPanel Stats'
    Affected if The version number is 78.0.44 or lower in the 78.x branch, or 84.0.19 or lower in the 84.x branch, or falls between 77.9999.110-78.0.44, or 83.9999.115-84.0.19
  2. Verify if demo accounts exist on the system
    List accounts with 'whmapi1 listaccts' and check for user type 'demo' or inspect /var/cpanel/users/ directories for demo account markers, or use 'grep -r "demo" /var/cpanel/users/'
    Affected if Any demo accounts exist on the server
  3. Check if Passenger applications are configured
    Inspect /var/cpanel/passenger/ or /etc/passenger.* configs, or look for .rb files in /usr/local/cpanel/Base/Addon/ Passenger directories, or check cPanel 'Passenger' application settings in user cPanel interfaces
    Affected if Any Passenger applications are deployed or configured on the server
  4. Review API access controls for PassengerApps
    Examine /var/cpanel/api endpoints for PassengerApps and check /var/cpanel/users/ for API token permissions related to passenger app management
    Affected if API tokens or access controls permit low-privilege users to manage Passenger applications

You are affected if your cPanel version is in the vulnerable range AND demo accounts exist or Passenger applications are configured on the server.

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 78.0.45 / 84.0.20 or later
Fixed in 78.0.4584.0.20
Interim mitigation

Upgrade cPanel to version 84.0.20 or later. If immediate patching is not possible, consider restricting or disabling demo accounts and reviewing API access controls.

Recommended fix High confidence

84.0.20 (or 78.0.45 for 77.x branch)

  1. 1. Identify current cPanel version by running: /usr/local/cpanel/cpanel -V
  2. 2. Determine which upgrade path applies: if on 77.x branch, upgrade to 78.0.45; if on 83.x branch, upgrade to 84.0.20
  3. 3. Schedule upgrade during a planned maintenance window
  4. 4. Create a full backup of cPanel configuration: cp -a /var/cpanel /var/cpanel.backup
  5. 5. Run cPanel update via: /usr/local/cpanel/scripts/upcp --force
  6. 6. Alternatively, force specific version: /usr/local/cpanel/scripts/upcp --force -v
  7. 7. Verify upgrade completed successfully: /usr/local/cpanel/cpanel -V
  8. 8. Confirm version is >= 84.0.20 or >= 78.0.45
Caveat Review cPanel release notes for 78.0.45 and 84.0.20 for any breaking changes specific to your configuration

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

Fix this in Cpanel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

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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-2020-10121 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