CVE-2017-18388
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 · uneditedcPanel before 68.0.15 can perform unsafe file operations because Jailshell does not set the umask (SEC-315).
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 confidenceIn cPanel versions before 68.0.15, the Jailshell restricted shell environment fails to properly set the umask (user file creation mask). This causes files and directories created within Jailshell to have overly permissive default permissions (e.g., 666 or 777 instead of the expected 644/755), potentially exposing sensitive files to unauthorized access.
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>= 61.9999.55, < 62.0.35>= 63.9999.74, < 64.0.42>= 65.9999.38, < 66.0.34>= 67.9999.64, < 68.0.15CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
-
Identify cPanel versionRun '/usr/local/cpanel/cpanel -V' or check '/usr/local/cpanel/version' to obtain the installed cPanel version number.Affected if The version falls within any of these ranges: 61.9999.55 to 62.0.34, 63.9999.74 to 64.0.41, 65.9999.38 to 66.0.33, or 67.9999.64 to 68.0.14.
-
Determine if Jailshell is in useCheck /etc/passwd for users with '/bin/jailshell' or '/usr/local/cpanel/bin/jailshell' as their login shell, or query cPanel's userdata for accounts using Jailshell.Affected if Any user account has Jailshell set as their shell and the cPanel version is in the affected ranges.
-
Verify umask setting within JailshellLog in via Jailshell and run 'umask' to display the current umask value, or inspect /var/cpanel/users/username files for shell configuration.Affected if The umask returns 0000, 0002, or another overly permissive value (e.g., not 0022 or more restrictive).
-
Test file creation permissions in JailshellAs a Jailshell user, create a new file (touch /tmp/testfile) and a new directory (mkdir /tmp/testdir), then check permissions with 'ls -la /tmp/testfile' and 'ls -ld /tmp/testdir'.Affected if The file shows permissions 666 or higher (e.g., 777) instead of the expected 644, or the directory shows 777 instead of 755.
A user is affected if they run a cPanel version in the vulnerable ranges AND have accounts using Jailshell with an incorrect umask causing files to be created with overly permissive permissions.
Generated from the published advisory. Verify against your own configuration.
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 data62.0.3564.0.4266.0.34
Update cPanel to version 68.0.15 or later to ensure Jailshell properly sets a restrictive umask. Alternatively, explicitly configure umask in startup scripts or contact cPanel support for patch options on legacy versions.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-18388 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2017-18388 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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