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CpanelApplication

CVE-2017-18451

MEDIUM · 5.3 CVSS v3.0 Published 2019-08-02
Fix available
A fix is available. Upgrade to 56.0.49 / 58.0.49 or later.
See remediation →
62/100
Remediation priority · Elevated
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 64.0.21 allows attackers to read a user's crontab file during a short time interval upon a cPAddon upgrade (SEC-257).

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

Race condition in cPanel before 64.0.21 allows attackers to briefly read a user's crontab file during a cPAddon upgrade due to improper file permission handling during the upgrade process (SEC-257).

MitigationUpdate cPanel to version 64.0.21 or later to patch the race condition vulnerability in the cPAddon upgrade process.

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:>= 56.0.1, < 56.0.49>= 58.0.3, < 58.0.49>= 60.0.3, < 60.0.43>= 62.0.1, < 62.0.24>= 64.0.0, < 64.0.21

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
Low
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 installed cPanel version
    Run `cat /usr/local/cpanel/version` or access WHM > Server Information to view the cPanel version
    Affected if The version falls within any of these ranges: 56.0.1 to 56.0.48, 58.0.3 to 58.0.48, 60.0.3 to 60.0.42, 62.0.1 to 62.0.23, or 64.0.0 to 64.0.20
  2. Verify cPAddons are in use
    Check for installed cPAddons in /var/cpanel/addons/ or via WHM > cPAddons.com
    Affected if Any third-party cPAddons are installed on the server
  3. Confirm upgrade logging or recent upgrade activity
    Review /var/log/cpanel.log or /var/log/cpaddons.log for recent cPAddon upgrade operations
    Affected if cPAddon upgrades have been performed on the server while running an affected version
  4. Check for crontab file accessibility
    Inspect /var/spool/cron/ directory permissions and review if any unauthorized access logs exist
    Affected if Crontab files exist for user accounts and the system was running an affected version during upgrade operations

A user is affected if their cPanel version falls within the vulnerable ranges AND cPAddon upgrades have been performed 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.

From vendor data
Upgrade available Upgrade to 56.0.49 / 58.0.49 / 60.0.43 or later
Fixed in 56.0.4958.0.4960.0.43
Interim mitigation

Update cPanel to version 64.0.21 or later to patch the race condition vulnerability in the cPAddon upgrade process.

Fix this in Cpanel Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.

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-2017-18451 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