CVE-2016-10856
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 11.54.0.0 allows subaccounts to discover sensitive data through comet feeds (SEC-29).
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 confidencecPanel before version 11.54.0.0 contains an information disclosure vulnerability where subaccounts (lower-privileged users) can access sensitive data through comet feed endpoints that they should not have authorization to view. The comet (long-polling/push) mechanism improperly exposes data between different account privilege levels.
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>= 11.48.0.5, < 11.48.4.8>= 11.50.0.4, < 11.50.3.1>= 11.51.9999.98, < 11.52.0.23>= 11.52.1.0, < 11.52.1.1CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/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 checksWork through these to decide whether this CVE applies to you.
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Check cPanel versionRun '/usr/local/cpanel/cpanel -V' or access WHM > Server Status > cPanel Version to retrieve the installed cPanel versionAffected if The installed version is 11.48.0.5 or higher but below 11.48.4.8, OR 11.50.0.4 or higher but below 11.50.3.1, OR 11.51.9999.98 or higher but below 11.52.0.23, OR 11.52.1.0 or higher but below 11.52.1.1. These are the vulnerable version ranges.
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Identify if subaccounts existCheck for subaccount users by running 'ls /var/cpanel/subscriptions' or listing users with '/scripts/listacct' and review if any accounts have associated subaccounts under themAffected if Any subaccounts (lower-privileged users) exist in the cPanel environment, as the vulnerability allows these subaccounts to access data outside their authorization level.
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Review comet feed access logsExamine cPanel access logs in /usr/local/cpanel/logs/ for unusual comet endpoint requests, or check /var/log/cpanel-api-log for API calls to comet-related endpointsAffected if Subaccounts are making requests to comet feed endpoints that should be restricted to higher privilege levels, indicating exploitation of this vulnerability.
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Audit subaccount permission boundariesReview which data and endpoints each subaccount should have access to by checking /var/cpanel/users/ for user files and their associated privilegesAffected if Subaccounts have access to data, files, or endpoints that belong to other accounts or the root account, suggesting unauthorized data exposure through the comet mechanism.
You are affected if your cPanel version falls within any of the four vulnerable ranges AND you have subaccounts configured, as the vulnerability allows lower-privileged subaccounts to view data they should not access through comet feed endpoints.
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 data11.48.4.811.50.3.111.52.0.23
Upgrade cPanel to version 11.54.0.0 or later to obtain the SEC-29 patch. If immediate patching is not feasible, audit subaccount permissions and monitor comet feed access patterns for unauthorized data exposure.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2016-10856 — 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-2016-10856 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
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- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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